CHAUrAUQUA 

OTEMRY/^ND  SCIENTIFIC 

CIRCLE 


THE  GREAT  WORLD^S  FARM 
SELINA    GAVE 


QlilF  i.  B.  Ml  SJtbrarg 


Nnrtlj  (Earnltna  BtnU 
MnttJFraitg 


0^81 
GP  80 
1902 


This  book  was  presented  by 

William  J.  Rose 


THIS  BOOR  IS  DUE  ON  THE  DATE 
INDICATED  BELOW  AND  IS  SUB- 
JECT TO  AN  OVERDUE  FINE  AS 
POSTED  AT  THE  CIRCULATION 
DESK. 


50M/2-78 


The  Great  World's 
Farm 


BY 

SELINA  GAVE 

AUTHOR  OF 

THE  WORLD'S  LUMBER  ROOM,"  "COMING."  ETC. 

By  Permission  of  The  Macmillan   Co. 


"  The  world  is  one  vast  garden,  bringing  forth  crops  of  the  most 
luxuriant  and  varied  kind,  century  after  century,  and  millennium 
after  millennium.  Yet  the  face  of  Nature  is  nowhere  furrowed  by 
the  plough,  no  harrow  disintegrates  the  clods,  no  lime  and  phos- 
phates are  strewn  upon  its  fields,  no  visible  tillage  of  the  soil 
improves  the  work  on  the  great  world's  farm.'''' 

H.  Drummond,  ''Tropical  Africa'' 


NEW  YORK        CHAUTAUQUA        SPRINGFIELD        CHICAGO 

Ete  Ottautaucjua  ^^cess 


Lakeside  Press,  Chicago,  III.,  U.  S.  A. 


.  -  /^, 


CONTENTS 


CHAPTER 


PAGE 

I.    Introductory j 

II.    Pioneer  Laborers j. 

III,  Soil-Makers       -        -       .       .        .  -,. 

IV.  Soil-Carriers «^ 

V.    Soil-Binders       ---...  40 

VI.    Field-Laborers     - 47 

VII.     F  iEL.Tf-LABORERS— continzied      ...  55 

VIII.    Water      - 66 

IX.    Deserts 81 

X.    Roots iqq 

XI.    Food  from  the  Soil 114 

XII.    Leaves  and  Their  Work   -        -       .       .  130 

XIII.  Climate -  149 

XIV.  Blossom  and  Seed        -       .       .       .       .  161 
XV.    The  Golden  Rule  for  Flowers  -        -        -  178 

XVI.    Guests  Welcome  and  Unwelcome  -  196 

XVII.    Seed-Scattering       -        -        -       -       -        -  214 

XVIII.    Seed-Carriers       .-...-  225 

XIX.    Chances  of  Life 237 

XX.    Friends  and  Foes         .       .       .       .       .  256 

XXI.    Nature's  Militia 267 


PREFACE 

This  edition  of  the  Great  World's  Farm  has  been 
somewhat  abridged  from  the  original  English  edition 
in  order  to  bring  it  within  the  limits  required  for 
books  of  the  Chautauqua  Reading  Circle.  No  essen- 
tial features  of  the  work,  however,  have  been  elimi- 
nated, and  the  chapter  divisions  remain  the  same  as 
in  the  larger  edition,  with  the  exception  of  the  last, 
''Man's  Work  on  the  Farm,"  which  has  been  omitted 
entirely. 

''Readers  of  mature  years  can  hardly  fail  to  find 
in  this  volume  some  facts  that  are  new  to  them,  some 
suggestions  of  a  wider  interpretation  of  nature  or  of 
a  more  accurate  perception  of  its  interrelations,  or 
some  fresh  cause  for  intelligent  wonder." 


THE   GREAT  WORLD'S   FARM 


CHAPTER  I 

INTRODUCTORY 

What  would  the  learned  writer  of  the  old  Eton  geog- 
raphy of  sixty  years  ago  say  to  the  statement  that  the  whole 
earth  is  one  great  farm  or  garden,  almost  everywhere 
covered  with  vegetation,  and  ''bringing  forth  crops  of  the 
most  luxuriant  and  varied  kind"?  This  was  certainly 
very  far  from  being  his  own  idea,  for  he  informed  his 
students  that  at  least  one  of  the  ''quarters"  of  the  world 
was  little  more  than  "a  vast,  sandy  desert." 

Such  was  his  description  of  the  great  continent  of 
Africa,  where,  according  to  him,  there  was  no  cultiva- 
tion except  in  the  immediate  neighborhood  of  a  river  or 
spring,  "all  the  rest  being  one  wide  tract  of  utter  desola- 
tion"; and  he  went  on  to  say:  "These  cultivated  places, 
appearing  like  islands  or  oases  in  the  great  desert,  caused 
some  of  the  ancients  to  compare  the  whole  continent  to  a 
panther's  skin,  dotted,  as  it  were,  with  spots  of  fertility 
surrounded  by  a  brown  and  burning  desert." 

As  a  matter  of  fact,  nothing  could  "more  wildly  mis- 
represent the  truth"  than  this  description;  but  it  was 
written  before  the  interior  of  Africa  had  been  explored, 
and  the  old  geographers,  feeling,  it  would  seem,  obliged 


12  The  Great  World's  Farm 

to  say  something,  were  very  much  in  the  habit  of  writing 
'* desert"  across  those  regions  of  the  earth  which  were  to 
them  ''unknown." 

These  imaginary  deserts,  which  once  occupied  so  large 
a  space  in  our  maps,  are,  however,  fast  shrinking  and 
dwindhng  away  before  the  face  of  the  explorer,  until  there 
are  few  if  any  left.  The  last  so-called  desert  in  America 
was  that  to  the  west  of  the  United  States,  and  that 
vanished  some  five  and  twenty  years  ago,  when  Mr.  Hep- 
worth  Dixon  said  of  it:  *'It  has  retreated  further  and 
further,  and  has  taken  its  last  stand  behind  the  Missouri, 
where  I  faced  it,  and  now  I  can  assure  you  that  I  have 
been  right  through  the  Great  Prairie,  and  desert  there 
is  none.  The  prairie  is  the  pasture-land  of  the  world — 
already  prepared;  that  is,  to  afford  an  ample  livelihood  to 
man's  flocks  and  herds  as  soon  as  he  should  choose  to 
make  use  of  it;  and  certainly,  therefore,  no  desert,  though 
''only  an  Indian  hunting-ground!" 

But  still,  it  may  be  said,  there  is  a  wide  difference 
between  a  desert  and  a  farm.  If  the  prairie  is  not  bare, 
at  least  it  is  uncultivated;  and  the  word  "farm"  suggests 
the  idea  of  plows  and  harrows,  orderly  crops,  sheep,  and 
cattle.  Very  true;  but  because  nature  farms  in  ways  of 
her  own,  on  a  large  scale  and  without  fuss,  while  man 
farms  in  his  way  on  a  small  one,  and  lets  all  the  world 
know  what  he  is  doing,  is  that  any  reason  for  denying  to 
nature  the  name  of  "farmer".? 

How  much  of  the  earth  has  man  brought  under  culti- 
vation? In  Europe,  where  he  has  done  most,  the  propor- 
tion varies  from  little  more  than  a  twentieth  (in  Sweden), 
to  a  little  more  than  one-half  (in  Belgium).  Supposing 
that  he  farms,  or  "improves,"  one-tenth  of  the  land  all 


Introductory  o 

the  world  over — and  he  certainly  does  not  do  more  at 
present— what  becomes  of  the  other  nine-tenths?  It  is 
not  a  desert,  it  does  not  lie  idle;  with  but  few  excep- 
tions, indeed,  it  is  covered  with  crops  of  one  sort  or 
another;   for  the  world  is  a  green  world,  not  a  brown  one. 

But  where  crops  are  grown  century  after  century, 
millennium  after  millennium,  no  matter  whether  they  be 
wild  or  not,  there  must  needs  be  tillage,  and  that  of  the 
most  thorough  kind,  fully  deserving  the  name  of  farming, 
though  it  may  be  carried  on  without  steel  plows,  and  so 
quietly  as  to  escape  our  notice. 

There  are  vast  pasture-lands  here,  there  are  extensive 
forests  there;  there  are  woods,  jungles,  heaths,  moors, 
downs,  but  they  have  all  been  planted;  and  the  soil  was 
prepared  in  the  first  instance,  and  has  been  renewed  since, 
by  laborers  who  are  not  less  truly  deserving  of  the  name 
of  laborer  than  the  plowman,  though  they  do  not  work 
with  his  implements. 

When  Captain,  afterwards  Sir,  Francis  Head,  traveled 
nine  hundred  miles  across  the  Pampas,  he  saw  to  his 
surprise,  first,  one  hundred  and  eighty  miles  of  the  most 
luxuriant  clover  and  wild  artichokes;  then  an  unbroken 
stretch  of  long  grass,  four  hundred  and  fifty  miles  wide, 
without  a  weed;  and  finally,  growing  up  to  the  base  of 
the  Cordillera,  a  grove  of  low  trees  and  shrubs. 

Man  had  had  no  hand  in  preparing  the  soil  for  this 
grass  and  clover;  man  had  neither  sowm  them  nor  cared 
for  them  in  any  way:  yet  there  they  were,  just  as  good 
food  for  his  cattle  as  if  they  had  been  grown  on  the  most 
orderly  of  human  farms.  Surely,  then,  the  lands  of  the 
Pampas  had  been  "farmed"  most  successfully,  by  one 
means  or  another.     For  the  word  ''farm"  is  said  to  be 


4  The  Great  World's  Farm 

derived  from  an  Anglo-Saxon  verb  which  means  "to 
supply  with  food,"  and  certainly,  in  this  sense,  the  lands 
which  man  still  leaves  to  nature's  laborers  have  every  claim 
to  be  considered  as  one  vast  farm;  for  they  grow,  many 
of  them,  the  most  luxuriant  crops,  and  they  feed  more  live- 
stock than  can  be  numbered. 

Man  grows,  for  himself  and  his  live-stock,  a  few  vege- 
tables— about  two  hundred  and  fifty  species — and  he  has 
adopted,  and  partly  domesticated,  about  two  hundred  ani- 
mals. But  on  the  great  natural  farm  things  are  done  on 
a  very  much  grander  scale.  Here  the  species  of  crops 
grown  number  not  much  less  than  a  hundred  and  forty 
thousand;  and  the  different  species  of  live-stock  amount 
to  some  millions. 

With  so  many  animals  to  feed,  and  so  many  crops  to 
grow,  nature's  farm-laborers  do  not  allow  of  "deserts"; 
and  wherever  there  is  an  unoccupied  surface,  they  hasten 
to  take  possession,  and  if  possible,  sow  something  upon 
it,  if  it  be  but  a  lichen.  They  sow  even  the  little  heaps 
of  dust  which  collect  in  sheltered  nooks,  on  the  leads  of 
the  church-tower,  on  walls,  in  the  angles  of  masonry,  and 
make  them  bear  at  least  a  blade  or  two  of  grass,  and 
often  quite  a  crop  of  various  green  things.  Generally 
speaking,  it  is  only  by  recent  lava-fields,  and  the  loftiest, 
bleakest  peaks  of  rock,  that  these  energetic  laborers  are 
baffled,  and  then  it  is  only  for  a  time. 

Over  and  over  again,  as  Mr.  Ball  says,  he  was  told  in 
different  parts  of  the  world  that  such  and  such  a  spot 
was  entirely  devoid  of  vegetation;  or  in  other  words,  a 
desert;  and  over  and  over  again  he  found  it  to  be  quite 
a  mistake.  On  the  so-called  "bare"  peaks  of  the  Dolo- 
mite Mountains  he  always  found  a  "fair  number"  of  plants 


Introductory  5 

hidden  in  cracks  and  crevices;  even  at  Suez,  on  the  ex- 
posed, burnt-up  face  of  the  mountain  Djebel  Attakah,  he 
still  found  something,  and  in  the  northern  part  of  the 
Great  Sahara,  though  vegetation  was  scanty,  it  was  diffi- 
cult to  find  many  yards  together  that  were  actually  bare. 

In  fact,  Mr.  Ball  had  come  to  doubt  the  existence  of 
"deserts"  altogether  by  the  time  he  reached  the  "rainless 
zone"  of  Peru,  and  was  once  more  told  that  he  would 
find  no  vegetation  at  all.  Certainly  this  was  more  barren 
than  any  part  of  the  world  which  he  had  yet  seen,  except 
indeed  the  drifting  sands  above  Cairo;  yet  even  here  there 
were  plants,  stunted  bushes  in  the  gullies,  and  tiny  vege- 
tables in  the  depressions  where  the  scanty  rain  rests 
longest;  but  they  wanted  looking  for,  as  there  was 
scarcely  one  so  much  as  three  inches  high.  The  laborers 
had  done  their  best;  they  had  prepared  the  soil,  and  they 
had  sown,  but  they  had  been  hindered  from  growing  any- 
thing like  a  luxuriant  crop  by  want  of  water.  And  at 
one  place,  Tocopilla,  they  had  been  entirely  baffled;  for 
here  at  last  Mr.  Ball  found  his  desert — an  altogether 
barren  spot,  where  not  a  single  green  thing  was  to  be  seen, 
and  not  so  much  as  a  lichen  was  to  be  discovered,  even 
with  the  help  of  a  microscope. 

But  this  is  quite  an  exceptional  state  of  things,  due  to 
the  extreme  rarity  of  the  rain;  and  such  utterly  barren 
surfaces  are  not  only  very  few,  but  very  small,  compared 
with  the  whole  extent  of  the  farm — mere  spots,  in  fact, 
in  the  midst  of  generally  luxuriant  crops. 

In  most  cases  the  so-called  deserts  are  deserts  only  for 
want  of  water;  the  soil  has  been  carefully  made  ready, 
and  in  the  Great  Sahara  and  the  deserts  of  Egypt  it  is 
extremely   rich,  though    at    present    covered  with    sand. 


6  The  Great  World's  Farm 

What  it  might  be,  and  how  easily  it  might  be  made  to 
"blossom  like  the  rose,"  we  can  to  some  extent  guess, 
when  we  find  that  the  passing  showers,  which  are  all  that 
visit  the  deserts  of  Egypt,  are  sufficient,  scanty  as  they 
are,  to  awaken  "the  green  things  on  the  yellow  surface"; 
though  we  may  well  wonder  how  the  seeds  "could  germi- 
nate after  months  of  exposure  to  the  burning  sun." 

And  then,  again,  while  it  is  quite  certain  that  such 
vegetation  as  exists  in  these  regions  is  grown  entirely  by 
the  natural  laborers,  there  seems  also  good  reason  to  sup- 
pose that  man  actually  does  much  to  hinder  their  work. 

If,  for  instance,  man  and  his  domestic  animals  were 
banished  from  the  Arabian  and  African  deserts,  it  is 
believed  by  Mr.  Marsh  that  many  parts  of  them  would 
soon  be  covered  with  forests,  and  with  forests  would  come 
rain,  to  the  enormous  benefit  of  the  whole  region. 
Acacias  of  several  species  are  constantly  being  sown,  and 
they  sprout  up  plentifully  around  the  springs  and  winter 
watercourses,  while  grasses  and  shrubs  grow  up  under 
their  sheltering  shade.  But  these  latter  are  mown  down 
as  fast  as  they  grow  by  the  hungry  cattle  of  the  Arabs; 
and  even  the  trees  do  not  escape,  for  the  goat  devours  the 
seedlings  whenever  it  has  the  opportunity,  and  the  camel 
will  bite  through  thorny  branches  as  thick  as  the  finger, 
and  unfortunately  it  has  a  particular  liking  for  the  twigs, 
leaves,  and  seed-pods  of  the  acacia;  so  that  between 
them,  the  tree  of  the  desert  has  but  little  chance.  If  only 
they  were  left  undisturbed  for  a  few  years  these  spots 
would  be  covered  with  groves,  which  would  gradually 
extend  where  now  little  can  grow  but  the  foxglove  and 
colocynth. 

Still,  even  now,  these  deserts  cannot  be  called  bare. 


Introductory  7 

though  their  crops  are  scanty.  As  we  have  said  before, 
the  laborers  on  the  great  farm  do  not  allow  any  surface  to 
be  bare,  if  they  can  help  it,  and  they  work  as  if  it  were 
their  one  object  to  grow  as  many  crops  as  possible.  The 
very  snow-fields  and  ice-fields  are  not  allowed  to  lie  idle, 
for  there  is  soil  even  here,  and  it  must  not  be  wasted. 

Dust,  meteoric  dust  from  the  higher  regions  beyond 
our  atmosphere,  is  constantly  falling  all  over  the  earth, 
to  the  amount,  it  is  believed,  of  more  than  five  hundred 
thousand  tons  every  year;  and  though  being  scattered 
evenly  over  the  whole  surface,  it  must  be  spread  very  thin 
indeed;  still,  where  there  is  no  other  mineral  matter,  as 
on  the  snow  and  ice  fields  of  the  Arctic  regions,  it  is  quite 
perceptible,  and  it  is  enough  for  the  growth  of  such 
humble  vegetables  as  the  "Red  Snow,"  which  in  summer 
covers  the  white  surface  with  a  flush  of  rose  color  many 
miles  in  extent.  Nor  are  this  and  other  similar  minute 
plants  grown  to  no  purpose.  These  ''barren  fields"  are 
also  part  of  the  great  world's  farm,  an  outlying  part,  it  is 
true,  where  the  produce  is  not  large;  but  such  as  they 
are,  the  crops  are  needed,  for  there  are  glacier-fleas  and 
other  live-stock  even  here,  and  these  tiny  vegetables  sup- 
ply them  with  food. 

Nature's  laborers  are  such  zealous  and  thrifty  husband- 
men that  they  are  always  on  the  watch  to  occupy  every 
inch  of  space  where  anything  can  be  grown  the  moment 
it  is  vacated,  and  even  before.  They  will  overrun  our 
gravel  paths,  and  grow  grass  in  our  streets  if  allowed, 
and  they  will  take  but  a  very  short  time  to  convert  the 
most  highly  cultivated  garden  into  a  wilderness  without 
any  trace  of  a  path  in  it,  if  it  be  given  up  to  them.  This 
is  true  even  in  such  temperate  climates  as  our  own,  but  in 


8  The  Great  World's  Farm 

warmer  latitudes  the  incessant  struggle  of  the  wild  crops 
to  invade  and  recover  the  ground  which  they  have  lost  is 
still  more  marked. 

At  Para,  in  Brazil,  for  instance,  we  are  told  that  every 
lane,  yard,  and  square  is  a  battle-ground.  Even  the  roofs 
and  cornices  of  some  of  the  public  buildings  are  occupied 
by  plants  or  small  trees,  which  wave  their  feathery  heads 
aloft  like  flags  of  triumph  in  defiance  of  the  enemy.  The 
city  is  hemmed  in  by  a  wall  of  tropical  forest,  consisting 
of  giant  trees,  palms,  and  tangled  creepers,  which  ever 
and  anon  send  out  skirmishers  to  try  and  effect  a  lodg- 
ment in  the  enemy's  territory;  and  so  well  do  they  suc- 
ceed where  circumstances  favor  them,  that  a  large  square, 
which  was  cleared  and  turfed,  but  left  unguarded,  was 
covered  in  five  years'  time  with  a  tangled  mass  of 
vegetation  fifteen  feet  high,  and  denser  than  the  virgin 
forest. 

For  there  is  no  lack  of  laborers  on  the  great  farm. 
They  are  employed  by  the  million  in  all  parts  of  it,  and 
though  they  are  always  ready  to  reclaim  any  portion  which 
has  been  taken  from  them,  they  nevertheless  attend  im- 
partially to  the  whole — the  small  part  which  man  has 
taken  under  his  own  care,  as  well  as  that  which  he  leaves 
at  present  entirely  to  their  management. 

And  a  very  sorry  condition  the  human  farmer's  fields 
would  be  in  if  they  were  left  to  himself  alone,  in  spite  of 
all  his  improved  modern  appliances  and  scientific  knowl- 
edge. 

"It  is  an  easy  error  to  consider  that  he  who  has  tilled 
the  ground  and  sown  the  seed  is  the  author  of  his  crop." 
And  for  the  most  part,  perhaps,  the  farmer  realizes  but 
little  of  the  vast  debt  which  he  owes  to  the  unseen,  un- 


Introductory  g 

noticed,  and  often  abused,  laborers  who  are  incessantly  at 
work  for  him. 

Of  course,  he  knows  very  well  that  he  cannot  do  with- 
out sun  and  rain,  and  he  will  readily  allow  that  dew,  frost, 
and  wind  are  useful,  and  that  at  present  he  could  hardly 
do  without  them ;  but  grant  him  these — and  what  are  they 
after  all  but  laborers  borrowed  from  the  larger  farm — and 
surely  his  improved  plows  and  harrows  and  his  patent 
manures  will  be  able  to  manage  the  rest.  In  the  days 
when  a  forked  stick  was  the  best  plow,  no  doubt  things 
were  different,  and  the  farmer  was  more  dependent  upon 
what  the  natural  laborers  were  pleased  to  do  for  him,  but 
now! 

Well,  let  him  try!  There  is  an  island  just  risen  above 
the  waves  here,  or  there  is  a  stream  of  cooled  lava  there — 
nice,  fresh,  virgin  surfaces  both  of  them,  where  nature's 
husbandmen  have  not  yet  been  at  work,  so  that  he  may 
keep  either  to  himself,  and  show  what  he  can  do  when  he 
is  not  interfered  with.  Let  him  try  his  modern  steel  plow, 
driven  by  steam,  too,  if  he  will,  upon  either  of  these. 

But  there  is  no  soil!  Of  course  not;  is  the  soil  put 
ready  for  nature's  laborers.?  Do  they  not  have  to  make 
it,  and  out  of  these,  or  similar  materials.?  But  one  cannot 
plow  the  bare  rock,  even  w^ith  the  help  of  steel  and  steam; 
and  before  these  can  do  anything  with  it,  it  must  be 
broken  up  and  crumbled  by  other  workers,  much  more 
humble  and  feeble  in  appearance,  most  of  them  absolutely 
noiseless,  some  quite  invisible,  and  yet — far  more  power- 
ful. 

Wonderful  things,  no  doubt,  are  being  done  with 
machinery,  and  the  time  may  possibly  come  when  we 
shall    be   able  to  grind  up   the  rock  without   too  great 


lo  The  Great  World's  Farm 

expenditure  of  time  and  labor;  but  even  then,  powdered 
rock  is  not  soil,  and  will  not  grow  any  crop  worthy  of  the 
name.  It  must  be  mixed  as  well  as  pounded  before  it 
can  be  converted  into  fertile  soil,  such  as  the  farmer  will 
find  it  worth  his  while  to  cultivate.  And  who  is  to  mix 
it.?  It  will  not  pay  him  to  attempt  the  work  himself  on 
any  large  scale;  but  it  has  been  done,  and  is  constantly 
being  done,  on  all  parts  of  the  great  natural  farm. 

On  the  whole,  then,  the  farmer  will  probably  find  it 
best,  at  least  for  the  present,  to  accept  what  has  been 
done  for  him.,  and  to  cultivate  the  soil  which  he  finds 
ready  made. 

"Ready  made?"  but  doesn't  he  still  have  to  plow  it, 
and  harrow  it,  and  manure  it?  To  be  sure;  but  this  is  no 
more  than  has  to  be  done,  and  is  done,  by  the  natural 
husbandmen  also  all  the  world  over.  Crops  cannot  be 
grown  year  after  year,  for  many  years  in  succession,  with- 
out constant  labor.  For  every  crop  takes  something 
from  the  soil,  and  the  loss  has  to  be  made  good.  The 
clods  must  be  broken  up,  too,  or  the  air  and  rain  cannot 
enter  freely,  and  the  roots  cannot  make  their  way  through 
the  soil.  And  this  the  farmer  must  do  as  best  he  can, 
with  his  plow  and  harrow;  but  these  are  at  best  only 
clumsy  instruments,  and  they  are  not  enough  by  them- 
selves. If  the  fields  were  deserted  by  the  ''natural  plow- 
men, ' '  the  worms,  and  others,  the  farmer  would  speedily 
find  that  his  plows  could  accomplish  only  the  rough  part 
of  the  work.  And  it  is  much  the  same  with  the  harrows; 
they  cannot  do  the  fine  work  of  the  great  "natural  har- 
row," the  frost,  which  crumbles  the  soil,  grain  by  grain, 
till  it  is  reduced  to  the  condition  of  dust  and  ashes,  ready 
for  sowing. 


Introductory  .  1 1 

And  now  surely  the  farmer  may  put  in  his  seed  and 
feel  that  if  only  seasonable  weather  be  granted  him  he 
may  be  quite  independent  of  further  help  from  his  humble 
fellow-laborers.  The  "if,"  to  be  sure,  is  rather  a  great 
and  important  **if, "  and  altogether  beyond  his  own  con- 
trol; but  granted  the  weather,  may  he  not  go  on  and 
prosper? 

Not  unless  he  is  prepared  to  pay  a  whole  army  of 
boys  to  keep  off  marauders;  and  even  then  he  would 
probably  find  himself  worsted  in  the  battle  with  slugs,  and 
snails,  and  grubs,  for  these  creatures  have  an  especial 
fondness  for  seedlings,  wild  and  cultivated.  We  are  told, 
for  instance,  by  the  Rev.  F.  Morris,  that  out  of  five  hun- 
dred and  four  grains  of  rape  planted  as  an  experiment, 
two  hundred  were  eaten  or  injured.  And  how  many  even 
of  these  would  have  escaped  if  "nature's  mihtia,"  the 
army  of  birds,  had  withdrawn  their  services.'*  Very  few, 
probably,  for  the  farmer  has  not  yet  invented  any  satis- 
factory substitute,  and  if  he  be  wise  he  will  certainly  wel- 
come them  in  his  fields,  and  be  glad  that  they  do  not  limit 
their  care  to  the  wild  crops  of  the  farm. 

But  when  the  crop  has  escaped  these  serious  perils  and 
dangers,  what  then.?  Even  then  the  farmer  will  not  in 
many  cases  have  any  harvest,  unless  nature  again  comes  to 
his  help  and  lends  him  a  fresh  set  of  workers  different  from 
any  hitherto  employed  in  his  service.  This  is  especially 
true  of  the  fruit-farmer  and  the  market-gardener.  The 
orchards  and  gardens  may  be  a  mass  of  blossom,  but  if 
they  are  left  to  themselves  at  this  critical  time  there  will 
be  few  apples,  strawberries,  or  raspberries,  and  absolutely 
no  melons  or  cucumbers,  no  matter  how  favorable  the 
weather  may  be.     And  the  same  holds  good  with  regard 


12  The  Great  World's  Farm 

to  many  another  crop.  Help  is  needed  if  they  are  to 
bring  their  fruit  to  maturity,  and  this  help  the  grower  is, 
generally  speaking,  quite  unable  to  give;  that  is  to  say, 
he  may  be  able  to  give  it  here  and  there  in  a  few  instances, 
but  he  would  be  powerless  in  an  orchard,  and  would  not 
be  able  to  afford  the  time  necessary  to  do  the  delicate 
work  required  in  a  single  strawberry  bed.  Again,  there- 
fore, he  must  look  to  nature's  laborers  for  assistance. 

Take  the  following  example,  for  instance:  In  his 
garden  at  Santo  Domingo,  Nicaragua,  Mr.  Belt,  the 
naturalist,  sowed  some  scarlet-runner  beans.  The  soil 
was  good,  and  the  climate  was  favorable  to  bean  life,  and 
the  scarlet-runners  grew  and  flourished,  and  finally  blos- 
somed abundantly. 

But  it  was  finally!  for  here  their  career  ended.  They 
did  not  produce  a  single  bean  among  them,  simply  because 
the  right  laborers  were  not  at  hand  to  give  the  requisite 
help. 

The  garden  in  which  the  beans  grew  had  been  recently 
taken  from  the  forest,  by  which  it  was  still  surrounded; 
and  that  the  laborers  in  this  part  of  the  farm  v/ere  not  idle 
was  quite  evident  from  the  abundant  luxuriance  of  the 
vegetation.  But  it  was  tropical  vegetation,  and  as  it  did 
not  include  scarlet-runners,  these  were  in  the  position  of 
foreigners,  whose  appeals  for  assistance  were  not  under- 
stood. It  was  in  vain  they  put  forth  the  bright  flowers, 
which  were  well-known  signals  in  their  native  land,  and 
would  there  have  brought  them  the  helpers  they  needed — 
no  one  noticed  them.  They  were  made  welcome  to  the 
soil,  the  rain,  and  the  sunshine,  and  then  they  were  left 
to  themselves  and  their  master,  with  the  result  already 
mentioned — no  fruit! 


Introductory  ij 

And  who  were  the  gardeners  whose  absence  proved  to 
be  of  such  vital  importance?  Humble  bees,  only  humble 
bees!  and  indeed,  only  the  particular  species  of  humble 
bees  which  wait  upon  scarlet-runners.  There  were  plenty 
of  others,  but  they  did  not  understand,  though  very  prob- 
ably they  would  have  come  to  do  so  in  the  course  of  a  few 
seasons.  As  it  w^as,  however,  failing  these  insect  labor- 
ers, there  was  nothing  to  be  done — nothing  to  take  their 
place.  Man  has  not  yet  discovered  any  substitute  for  the 
bee. 

In  the  following  chapters  we  shall  consider  in  more 
detail  the  various  ways  and  means  by  which  the  work  of 
the  great  farm  is  carried  on  by  the  natural  laborers,  and 
also  some  of  the  changes  made  in  it  by  the  work  and 
unconscious  influence  of  man. 


QUESTIONS  FOR  REVIEW 

1.  How  have  our  ideas  of  the  fertility  of  the  earth   been 
changed  in  recent  years? 

2.  What  proportion  of  the  earth  in  Europe  has  been  brought 
under  cultivation? 

3.  How  do  the  animals  and  vegetables  used  by  man  com- 
pare in  number  with  nature's  supply? 

4.  Show  how  nature  makes  use  of   every  possible  oppor- 
tunity for  raising  crops. 

5.  How  do  man  and  his  animals  sometimes  help  to  increase 
the  desert  regions? 

6.  Show  how  the  farmer  is  dependent  at  every  step  upon 
nature's  laborers. 


CHAPTER  II 

PIONEER  LABORERS 

No  one  needs  to  be  told  that  all  living  things  require 
food  of  one  sort  or  another  to  keep  them  alive;  but  some 
people  have  fancied,  even  within  the  last  hundred  years, 
that  vegetables  had  such  delicate  appetites  as  to  need 
nothing  but  air  and  pure  water  for  their  sustenance.  As 
a  matter  of  fact,  however,  no  vegetables  live  upon  a  diet 
of  mere  air  and  water. 

But  then,  what  of  the  seaweeds  which  float  about  in 
the  ocean?  Are  there  not  vast  meadows  of  weed  far 
away  from  soil  or  even  rocks  of  any  kind.?  Does  not  the 
ocean,  moreover,  swarm  everywhere,  from  the  polar 
regions  to  the  equator,  with  microscopic  vegetables?  And 
is  it  not  a  fact  that  no  seaweeds,  not  even  those  which 
cling  to  the  rocks,  receive  any  of  their  nourishment 
through  their  roots,  and  therefore  must  live  upon  water? 
Quite  true  that  they  do  not  feed  by  means  of  their 
roots — indeed,  no  seaweeds  possess  true  roots;  and  it  is 
quite  true,  also,  that  they  live  upon  what  they  obtain  from 
the  water,  but  surely  the  taste  of  it  is  sufficient  to  prove 
that  it  is  not  mere  water. 

There  is  no  such  thing  as  pure,  absolutely  pure,  water 
in  nature;  and  sea-water,  which  is  much  heavier  than 
fresh  water,  contains  thirty-five  parts  of  solid  matter  in 
every  thousand.  The  rivers  are  constantly  pouring  into 
it  small  quantities  of  every  sort  of  mineral  substance  that 

14 


Pioneer  Laborers  15 

can  be  dissolved,  while  the  sun  draws  up  from  it  almost 
pure  water,  leaving  the  salts  behind  to  accumulate  and 
help  to  feed  the  crops  of  seaweed,  besides  providing 
material  for  the  skeletons  of  corals  and  sponges  and  the 
shells  and  bones  of  other  sea-creatures.  All  plants,  then, 
are  alike  in  this,  that  they  live  upon  other  food  besides 
mere  air  and  water. 

We  may  easily  satisfy  ourselves  of  this  by  burning  a 
bit  of  wood,  a  few  grains  of  corn,  or  any  other  vegetable 
matter.  When  it  has  burned  as  long  as  there  is  anything 
to  burn,  and  all  gases  and  water  it  contained  are  driven 
away,  a  small  quantity  of  ash  will  remain,  consisting  of 
salts,  or  compounds  of  various  metals.  The  whole 
amount  is  usually  very  small — so  small  that  we  might  per- 
haps be  disposed  to  think  it  could  not  be  of  any  very  great 
consequence. 

If,  for  instance,  we  were  to  burn  a  hundred  grains  of 
wheat  so  thoroughly  that  nothing  but  ash  remained,  we 
should  find  the  whole  amount  of  this  to  be  equal  to  about 
two  of  the  grains,  or  less. 

However,  **many  a  mickle  makes  a  muckle, "  and 
when  we  consider,  not  single  plants  or  a  handful  of  grain, 
but  a  whole  crop,  the  amount  of  mineral  matter  becomes 
large  enough  to  look  important.  Thus,  while  a  pinch  or 
two  of  dust  might  represent  the  entire  amount  of  ash  of 
all  sorts  in  a  single  turnip  or  carrot,  there  are,  on  an 
average,  about  forty  pounds  of  lime  alone  in  twenty-two 
tons  of  turnips,  more  in  proportion  in  the  carrots,  and 
very  much  more  in  an  equal  weight  of  clover. 

The  mineral  substances  chiefly  taken  up  by  plants  are 
sulphur,  phosphorus,  silica,  potash,  soda,  lime,  iron, 
magnesia,  manganese,  together  with  mineral  compounds 


1 6  The  Great  World's  Farm 

of  the  two  gases  chlorine  and  fluorine.  All  these  are 
contained  in  the  rocks;  but  as  long  as  it  is  stored  in  the 
rocks  it  might  as  well  be  locked  up  so  far  as  most  of  them 
are  concerned,  for  they  cannot  get  at  it  or  make  use  of 
it.  The  stone  must  be  converted  into  soil  before  they 
can  turn  it  to  account;  and  how  is  this  to  be  accom- 
plished.? 

If  a  man  had  to  make  his  soil  from  the  rocks  before  he 
could  grow  his  crops,  he  would  have  to  begin  with  crow- 
bars and  pickaxes,  if  he  did  not  first  resort  to  blasting 
with  gunpowder  or  dynamite,  and  even  then  his  progress 
would  be  slow  and  laborious. 

Nature  usually  works  in  a  much  more  quiet  and  unob- 
trusive fashion,  but  there  are  times  when  she,  too,  has 
recourse  to  blasting  as  a  preliminary  measure.  She 
mines  the  rocks  and  shatters  them  by  means  of  the  earth- 
quake, compared  with  which  the  power  even  of  dynamite 
is  insignificant;  but  it  is  the  noiseless  and  often  invisible 
workers  who  accomplish  most,  for  they  are  at  work,  some 
or  other  of  them,  incessantly  during  every  moment  of 
every  hour,  day  and  night,  summer  and  winter,  through- 
out the  whole  year. 

Usually  the  first  of  the  silent  laborers  to  begin  work 
upon  the  rocks  are  also  the  invisible  ones — the  gases  of 
air  and  water,  which  wear  away  the  very  hardest  rocks  by 
degrees. 

The  two  gases  which  do  the  chief  part  of  the  chemical 
work  are  oxygen  and  carbon  dioxide,  formerly  called  car- 
bonic acid.  Rocks  containing  much  iron  are  especially 
open  to  the  attacks  of  the  one,  and  those  containing  lime, 
potash,  soda,  to  the  attacks  of  the  other.  We  are  all 
familiar  with  the  fact  that  iron  and  steel  become  covered 


Pioneer  Laborers  17 

with  rust  if  left  exposed  to  the  air.  Keys  rust  if  left  in 
their  locks,  and  even  pohshed  fire-irons  often  rust  in  the 
summer,  unless  they  are  oiled  or  greased,  and  so  protected 
from  the  air.  What  happens  in  these  cases  is  that  the 
oxygen,  always  present  both  in  the  air  itself  and  in  the 
watery  vapor  floating  in  the  air,  lays  hold  of  the  metal 
and  combines  with  it  to  form  a  compound  substance — an 
oxide — which  is  looser  and  softer,  and  takes  up  more 
room  than  the  metal  alone.  At  first  the  rust  is  a  mere 
reddish  brown  stain;  but  as  the  oxygen  eats  deeper  and 
deeper,  and  more  and  more  oxide  is  formed,  it  swells  up 
unevenly  above  the  surrounding  surface,  and  feels  rough 
to  the  touch.  It  is  so  soft  that  it  may  be  partly  rubbed 
off  by  the  finger,  and  when  the  rust  is  cleaned  away  there 
will  be  scars  and  indentations  left,  showing  how  much  of 
the  metal  has  been  removed. 

Very  many  rocks  contain  iron,  as,  for  instance,  the 
slates,  sandstones,  granites,  and  basalts,  some  more,  some 
less,  but  hardly  ever  in  a  pure  state.  The  basalt  of  the 
Giant's  Causeway  contains  so  much  iron  that,  on  those 
sides  which  are  most  exposed  to  the  weather,  it  not  only 
looks  rusty,  but  is  also  softer  on  the  surface  and  less  com- 
pact within,  for  nature's  laborers  do  not  generally  work 
singly  and  alone,  but  in  union  one  with  the  other,  and  the 
great  ally  of  oxygen  is  moisture. 

Let  us  take  basalt  as  an  example,  and  see  how  this 
rock  is  crumbled  into  soil.  In  perfectly  dry  air,  at  the 
ordinary  temperature,  oxygen  is  powerless  to  do  even  so 
much  as  tarnish  iron  in  the  mass,  though  it  would  have 
no  difficulty  in  reducing  it  all  to  oxide — that  is,  rust — if 
the  same  mass  of  iron  were  exposed  to  its  action  in  the 
form  of  powder.     Fire-irons  do  not  rust   in  winter,   or 


1 8  The  Great  World's  Farm 

when  in  constant  use,  because  the  fire  keeps  them  dry; 
they  do  rust  when  unused  in  summer,  because  natural  air 
is  never  perfectly  dry,  even  on  the  driest  summer  day, 
not  even  in  the  midst  of  the  parching  desert. 

But  if  iron  quickly  rusts  when  exposed  to  the  damp 
air  of  such  a  climate  as  ours,  we  all  know  how  much 
faster  it  does  so  when  actually  wetted;  and  therefore  it  is 
not  surprising  to  find  that  basaltic  and  other  rocks  con- 
taining much  iron  decay  more  rapidly  on  the  side  which 
faces  the  rainiest  quarter — not  that  the  force  of  the  rain 
makes  so  much  impression  on  them  as  on  softer  rocks, 
but  that  the  wet  enables  the  oxygen  to  work  faster.  The 
decay  is  not  confined  to  the  surface,  moreover,  for  all 
rocks,  even  those  which  are  most  close  and  compact  and 
are  called  impervious,  absorb  some  amount  of  moisture, 
and  this  also  finds  entrance  through  the  cracks  and  joints, 
from  which  no  large  mass  of  rock  is  ever  entirely  free. 
These  joints  are  especially  well  developed  in  the  basalt — 
an  ancient  lava — which,  in  coohng  down  from  the  molten 
state,  has  shrunk  and  contracted  into  columns  having  from 
three  to  nine  faces,  and  measuring  from  a  few  inches  to 
several  feet  across.  The  rain,  of  course,  easily  finds  its 
way  in  between  these  columns;  but  patches  of  wet  and 
brown  stains  are  also  found  actually  inside  the  columns 
themselves,  when  these  are  broken  open,  showing  that 
moisture  has  been  sucked  up  by  the  rock. 

Now  water  in  the  natural  state  always  contains  some 
amount  of  air  dissolved  in  it,  and  wherever  the  water  pene- 
trates, there  the  oxygen  of  the  air  penetrates  also,  and 
lays  hold  of  any  iron  that  comes  in  its  way,  as  we  see  by 
the  stains  that  it  has  done  in  this  instance. 

The  iron  of  the  basalt  is  not,  indeed,  pure  iron,  being 


Pioneer  Laborers  19 

already  combined  with  some  amount  of  oxygen,  but  it 
does  not  acquire  the  reddish  brown  color  of  what  we 
familiarly  call  *'rust"  until  it  has  absorbed  as  much  oxygen 
as  it  can  hold.  In  this  condition  it  is,  of  course,  heavier, 
and  as  we  have  seen,  softer  than  before,  and  is  therefore 
more  easily  washed  or  blown  away  from  the  surface.  But 
it  is  also  more  bulky,  and  takes  up  more  space  than  it  did 
before,  so  that  if  it  be  formed  inside  the  rock  where  it 
has  not  room  to  expand,  the  rock  is  cracked  by  it.  This, 
of  course,  opens  the  way  for  more  water  and  more  oxygen 
to  enter,  and  so  the  work  proceeds,  and  the  decay  goes 
deeper  and  deeper. 

We  have  chosen  iron-rust  as  a  sample  of  the  way  in 
which  oxygen  works  because  it  is  one  of  which  we  all 
know  something,  but  it  must  not  be  forgotten  that  this  is 
only  one  of  many  oxides  formed  in  the  rocks;  and  that 
whenever  oxygen  combines  with  any  other  substance  in  a 
rock  to  form  an  oxide,  it  makes  that  substance  take  up 
more  room  than  before,  and  so  the  rock  is  cracked  and 
crum.bled.  The  other  gas,  carbon  dioxide,  works  in  a 
different  way,  though  it  also  helps  the  oxygen  to  rust  iron 
faster  than  it  could  do  alone.  But  when  it  works  on  its 
own  account  it  is  by  combining  with  such  substances  as 
Hme,  potash,  soda,  and  magnesia,  which  it  makes  much 
more  soluble  than  they  were  before. 

Some  rocks  are  said  to  be  impervious,  or  ''water- 
proof, ' '  but  this  only  means  that  they  allow  water  to  enter 
so  very  slowly  that  unless  they  are  actually  soaking  in  it 
for  some  time  hardly  any  is  taken  up.  Water  has  some 
effect  upon  every  known  mineral,  unless  it  be  perhaps 
upon  gold  and  platinum.  But  water  in  nature  is  never 
perfectly  pure;   how  can  it  be,  since  it  dissolves  some, 


ao  The  Great  World's  Farm 

though  it  may  be  only  a  very  minute  quantity,  of  every- 
thing through,  or  over,  which  it  passes?  Its  dissolving 
powers  are  greatly  increased,  too,  by  the  addition  of  car- 
bon dioxide — the  gas  we  are  now  speaking  of — which  is 
being  constantly  produced  both  in  earth  and  air,  by  the 
decay  of  vegetable  matter  in  the  one,  and  by  the  lungs  of 
animals,  fires,  and  furnaces  in  the  other. 

The  rain  as  it  descends  from  the  clouds  washes  down 
with  it  some  of  this  gas,  and  if  it  comes  in  contact  with 
such  a  rock  as  limestone,  soon  makes  an  impression  upon 
it.  Chalk,  limestone,  and  marble  are  all  composed  of 
carbonate  of  lime,  softer  or  harder,  the  lime  being  already 
united  with  a  certain  quantity  of  carbon  dioxide.  But  in 
this  condition  it  dissolves  so  very  slowly  as  to  be  called 
insoluble  in  pure  water.  When  it  comes  in  contact  with 
the  gas,  however,  whether  in  air  or  water,  it  takes  up 
double  the  quantity  it  had  before,  and  is  converted  into  a 
double,  or  bicarbonate,  which  is  easily  dissolved  and 
washed  away. 

Even  rocks  which  consist  only  in  part  of  carbonate  of 
lime  are  open  to  the  attacks  of  carbon  dioxide.  For 
instance,  there  are  the  sandstones.  The  grains  are  hard 
enough,  being  composed  of  silica,  and  if  they  are  cemented 
together  with  silica,  too,  the  stone  is  one  of  the  most 
durable  that  can  be  found,  neither  water  nor  gases, 
together  or  separately,  being  able  to  make  much  impres- 
sion upon  it.  But  if  the  grains  are  cemented  together  by 
iron  oxide,  or  by  carbonate  of  lime,  it  is  quite  another 
matter.  Oxygen  or  carbon  dioxide  may  get  to  work  on 
the  cement,  and  as  that  is  removed  the  grains  fall  apart 
and  become  sand. 

But  nature's  laborers  proceed  upon  the  principle  that 


Pioneer  Laborers  21 

''union  is  strength,"  and  they  so  constantly  work  in  com- 
pany that  it  is  a  difficult  matter  to  apportion  the  results  of 
their  labors  exactly  each  to  each.  We  have  already  seen 
how  water  dissolves;  we  must  now  look  at  it  in  another 
capacity,  and  see  how  it  acts  the  part  of  crowbar  and 
pickaxe,  and  even  at  times  of  dynamite.  A  cubic  inch  of 
water,  when  converted  into  steam,  occupies  just  1,728 
times  as  much  space  as  it  did  before,  and  it  expands  with 
such  violent  force  as  to  shatter  the  rocks  beneath  which  it 
is  confined.  Such  explosions  as  this  sometimes  occur 
during  volcanic  eruptions,  water  having  found  its  way 
down  through  the  earth  till  it  has  come  into  contact  with 
some  mass  of  molten  lava,  which  has  converted  it  into 
steam,  and  made  it  a  powerful  engine  of  destruction. 
But  water  expands  also,  though  in  a  less  degree,  when  it 
is  converted  into  ice,  and  it  is  under  this  aspect  that  we 
are  most  famihar  with  its  doings. 

Water,  as  we  have  said,  finds  entrance  everywhere, 
more  or  less,  in  one  way  or  another,  and  wherever  it  is 
sufficiently  near  the  surface  to  freeze,  there  it  has  the 
effect  of  a  multitude  of  crowbars  and  chisels  of  all  sorts 
and  sizes  wielded  by  an  invisible  army  of  workmen.  It 
widens  every  crack  in  which  it  is  formed,  prizing  up  large 
masses  of  rock  many  tons  in  weight,  loosening  and  eventu- 
ally forcing  them  off,  and  also  doing  finer  work,  such  as 
chiseling  off  splinters  and  particles  of  all  sizes,  large  and 
small.  The  immense  piles  of  rubbish  which  strew  the 
surface  of  the  glaciers,  and  consist  of  sand,  grit,  and 
fragments  of  all  dimensions,  are  due  mainly  to  the  action 
of  the  frost,  which  in  mountain  regions  recurs  not  merely 
every  winter,  but  every  night  throughout  the  year. 

But  even  where  there  is  no  rain,  and  no  ice  can  there- 


11  The  Great  World's  Farm 

fore  be  formed  in  their  cracks  and  crevices,  the  rocks 
themselves  feel  changes  of  temperature;  and  where  these 
changes  are  sudden,  severe,  and  often  repeated,  no  rock 
is  strong  enough  to  stand  against  them.  The  rocks  of 
the  Sahara  and  other  similar  regions  are  crumbled  into 
sand  simply  by  the  intense  heat  of  the  day  and  the  sharp 
frost  at  night. 

When  the  Glass  Road  was  being  made  in  the  famous 
Yellowstone  Park  (Wyoming,  U.S.A.),  some  huge  blocks 
of  obsidian,  or  volcanic  glass,  were  found  to  come  in  the 
way;  and  as  they  were  too  hard  to  be  either  hewn  or 
drilled,  and  could  therefore  not  be  blasted,  the  engineer 
in  charge  had  large  fires  lighted  on  the  top.  When  the 
rocks  were  scorching  hot,  a  sudden  deluge  of  cold  water 
was  poured  upon  them  from  the  neighboring  lake,  and  by 
these  means  they  were  thoroughly  shattered.  This  is,  of 
course,  a  very  extreme  instance  of  the  effect  produced  by 
changes  of  temperature,  and  such  as  would  seldom,  if 
ever,  occur  in  nature;  but  it  may  serve  to  show  how  very 
real  these  effects  are. 

Of  the  other  ways  in  which  the  rocks  are  broken  up, 
it  will  not  be  needful  to  say  much.  We  must  pass  over 
with  brief  mention  the  work  done  by  sand,  set  in  motion 
by  wind  or  water,  which  cuts  and  polishes  the  very  hard- 
est rocks  when  driven  against  them  by  the  former,  and 
when  driven  by  water,  has  produced  the  great  canons,  or 
narrow  gorges  some  thousands  of  feet  in  depth,  with 
which  we  are  familiar  in  California. 

But  a  few  words  must  be  said  about  the  glaciers,  those 
frozen  rivers,  which  are  among  the  mightiest  of  nature's 
grinders.  Looking  down  upon  a  glacier,  and  seeing  it 
strewn  with  the  blocks  of  stone  and  vast  heaps  of  rubbish 


Pioneer  Laborers  '23 

which  have  fallen  upon  it  from  the  cliffs  above,  dislodged 
by  the  frost,  we  should  be  disposed  to  think  it  a  very 
rough  laborer  indeed,  merely  engaged  in  carting  away  the 
wreckage  made  by  others.  But  this  would  be  a  great  mis- 
take; for  the  glacier  is  a  giant  mill-stone,  pressing  upon  the 
rocks  beneath  with  a  power  which  is  simply  irresistible. 

Glaciers  move  on  in  solemn  silence,  it  may  be  at  the  rate 
of  perhaps  only  an  inch  or  two  in  the  twenty-four  hours, 
but  they  go  on  steadily  and  noiselessly,  and  as  they  go, 
they  grind  the  rocks  beneath  to  a  powder  so  fine,  that 
when  at  last  it  escapes  from  the  glacier-mill  in  the  stream, 
which  flows  out  from  beneath,  it  has  been  reduced  to 
nothing  but  mud. 

One  other  grinder,  equally  mighty  and  thorough,  but 
by  no  means  silent,  must  be  mentioned  in  conclusion. 
This  is  the  volcano,  which,  besides  pouring  forth  streams 
of  lava,  often  buries  the  surrounding  country  many  feet 
deep  in  the  finest  dust  and  ashes,  or  in  mud,  if  the  erup- 
tion be  accompanied,  as  it  often  is,  by  rain. 

But  the*  laborers  which  we  have  been  thus  briefly  con- 
sidering are  only  pioneers.  They  accomplish  only  the 
rougher  work  of  preparation,  and  very  much  remains  to 
be  done  before  anything  that  can  properly  be  called  **soil" 
is  ready  for  the  crops. 

QUESTIONS  FOR  REVIEW 

1.  Illustrate  the  fact  that  all  plants  require  other  food  than 
air  and  water. 

2.  Describe  the  action  of  oxygen  upon  iron. 

3.  What  effect  has  water  upon  minerals? 

4.  Show  how  carbon  dioxide  works  upon  the  rocks. 

5.  By  what  different  methods  does  water  break  the  rocks 
apart? 

6.  How  are  the  rocks  of  the  Sahara  crumbled? 

7.  By  what  agencies  are  the  rocks  ground  and  polished? 


CHAPTER  III 

SOIL-MAKERS 

Standing  before  some  bare  expanse  of  hard  rock,  we 
might  well  wonder,  if  we  knew  nothing  of  the  subject, 
how  it  should  ever  be  converted  into  a  surface  fit  for  the 
support  of  vegetation.  There  may  be  vineyards  close  by 
showing  that  it  has  been  done  in  other  instances;  but 
what  is  to  be  the  first  step? 

If  we  were  to  look  closely  at  the  seemingly  bare  sur- 
face, we  might,  and  in  most  cases  would,  find  that  it  was 
not  altogether  bare  and  barren.  We  might  need  a  micro- 
scope to  show  us  the  truth,  but  if  we  understood  what  we 
saw,  we  would  discover  that  the  rock  had  been  sown. 

The  pioneer  laborers,  far  from  finishing,  have  hardly 
begun  their  work  here,  but  seed  has  been  scattered  in  this 
unlikely  place;  and  if  we  look  at  what  has  been  done  in 
other  similar  places,  we  shall  see  that  it  has  not  been 
wasted. 

Floating  about  in  the  air,  invisible,  but  in  countless 
multitudes,  are — what  answer  to  the  seeds  of  other 
plants — the  spores  of  those  strange  forms  of  vegetation 
called  lichens,  which,  except  in  towns,  are  to  be  seen 
beautifying  every  old  wall,  roof,  and  tombstone.  They 
are  so  light  that  they  cannot  settle  at  all,  except  when  the 
air  is  still,  and  even  then  the  least  breath  would  disturb 
them. 

But  they  are  sticky,  and  this  stickiness  enables  them  to 
24 


Soil-Makers  25 

cling  fast  even  to  the  bare  rock.  Once  settled,  they  begin 
to  grow,  and  are  the  first  traces  of  vegetable  life  to  make 
their  appearance  upon  recent  streams  of  lava.  They  may 
truly  be  called  "traces,"  for  the  first-comers  are  nothing 
more  than  helpless  looking  stains,  or  dust,  hardly  notice- 
able except  by  those  on  the  lookout  for  them;  and  one 
would  have  said  anything  but  dangerous  to  the  rock, 
for  they  look  not  only  perfectly  inactive,  but  entirely 
hfeless. 

The  lava  has  resisted  for  some  time.  For  years  it  did 
not  even  cool,  and  it  has  scorched  innumerable  lichen 
spores  to  death  in  their  attempt  to  settle  upon  it.  Even 
when  the  surface  had  cooled  there  was  for  a  long  time 
heat  enough  within  to  dry  all  the  life  out  of  them;  while 
multitudes  have  found  the  glossy  surface  too  glossy  even 
for  their  powers  of  clinging,  and  have  been  blown  away 
as  fast  as  they  came.  There  are  some  streams  of  lava 
which  are  as  glossy  now  as  when  they  were  first  poured 
forth  three  or  four  hundred  years  ago,  and  no  lichens 
have  as  yet- managed  to  gain  a  footing  there.  But  they 
are  not  generally  kept  so  long  at  bay.  They  return  to 
the  charge  again  and  again,  helped  by  the  pioneers,  who 
have  also  been  at  work  meantime,  and  have  gradually 
roughened  the  surface  a  little,  or  at  least  have  taken  off 
some  of  the  glossiness;  and  at  last  the  spores  manage  to 
settle  and  fix  themselves  so  firmly  that  neither  wind  nor 
rain  can  dislodge  them,  and  they  begin  to  grow  and  spread 
at  their  ease. 

Then,  in  spite  of  what  was  said  in  the  previous  chap- 
ter, these  vegetables,  at  all  events,  must  live  on  air  and 
water? 

Not    at    all!     Lichens    are    very    substantial    feeders 


26  The  Great  World's  Farm 

indeed,  "and  consume  more  mineral  matter  in  proportion 
to  their  size  than  any  other  plants. 

But  if  it  is  locked  up,  and  not  available  until  the  rock 
is  crumbled  down  and  softened  enough  for  the  roots  to 
penetrate  into  it,  how  can  they  get  at  it? 

In  one  respect  lichens  are  like  seaweeds,  for  they  have 
no  roots  through  which  to  take  up  food.  But  they  are 
unlike  them  in  another,  for  they  do  feed  upon  the  rocks; 
and  even  these  first-comers,  the  humblest  members  of  the 
family,  mere  stains  in  appearance,  contrive  to  make  a 
living  wherever  they  can  gain  a  footing.  Not,  of  course, 
that  they  take  up  particles  of  stone,  but  being  all  of  them 
strongly  acid,  they  are  able  to  dissolve  it  first  and  then 
absorb  what  they  need;  and  though  they  are  at  first  so 
minute  as  to  be  almost  microscopic,  no  rock  can  resist 
them. 

The  ** stains"  spread  and  grow  and  decay,  and  by 
degrees  there  is  formed  from  their  remains  a  thin  film  of 
soil,  in  which  lichens  of  a  much  larger  growth  are  able  to 
flourish.  They  are  all  more  or  less  harsh  to  the  touch; 
and  the  ashy,  steely  grays,  and  rusty  browns,  and  the 
brilliant  yellow  and  orange  of  their  coloring  remind  one 
more  of  minerals  than  of  vegetables,  which  is  not  surpris- 
ing, considering  that  often  a  fifth  part  of  their  substance, 
and  sometimes  much  more,  consists  of  solid  matter  eaten 
from  the  rocks. 

When  the  lichens  have  had  possession  for  a  time,  and 
have  prepared  the  way,  they  are  followed  by  mosses, 
which  absorb  much  moisture  from  the  air,  and  help  to 
decay  the  rock  by  keeping  the  surface  damp;  for,  as  we 
have  already  seen,  where  water  is,  there  frost  and  gases 
can  get  to  work.     The  mosses  grow  and  die  in  their  turn. 


Soil-Makers  27 

and  their  remains,  with  those  of  lichens  and  loosened 
particles  of  rock,  as  well  as  the  dead  bodies  of  such  mi- 
nute insects  as  may  have  found  a  dwelling  among  them, 
together  form  something  deserving  the  name  of  mold, 
which  will  support  plants  of  quite  large  size.  These  are 
followed  by  dwarf  shrubs,  whose  roots  help  on  the  work 
more  rapidly;  and  in  a  century,  more  or  less,  the  stream 
of  lava  is  usually  converted  into  soil  fit  for  the  planting 
of  vineyards  and  gardens. 

Lichens  attack  not  only  lava,  however,  but  also  gran- 
ites, slates,  and  even  hard  crystalHne  quartz-rock,  wherever 
there  is  sufficient  moisture.  No  rock  is  proof  against 
them;  almost  any  climate  suits  them,  hot  or  cold,  moist 
or  dry,  and  they  are  the  last  signs  of  vegetation  to  be  lost 
sight  of  by  the  mountaineer  as  he  ascends  towards  the 
region  of  perpetual  snow  and  bare  peaks,  whither  even 
they  are  unable  to  follow. 

The  so-called  violet-stone,  found  on  the  summit  of  the 
Brocken,  is  nothing  but  bare  granite,  covered  with  a  film 
of  what  looks  like  scarlet  dust,  which  smells  like  violets, 
especially  on  being  rubbed.  It  looks  so  perfectly  harm- 
less, that  one  can  hardly  beheve  it  possible  it  should  affect 
the  solid  granite  in  any  way.  Yet  it  does;  to  a  very 
small  extent,  indeed,  but  just  sufficiently  to  prepare  the 
way  for  two  large  brown  lichens,  which  are  the  next  to 
make  their  appearance;  and  then  the  work  proceeds  more 
rapidly,  in  the  way  already  described,  until  at  last  tall  pine- 
trees  rear  their  heads  and  find  sufficient  food  and  foot- 
hold, where  but  a  few  years  before  there  was  nothing  but 
a  bare  surface. 

The  pines  are  much  more  imposing  in  appearance,  and 
look  capable  of  much  greater  exertion  (as  they  are  in  some 


28  The  Great  World's  Farm 

ways),  but  they  could  not  have  done  what  the  hchen  does; 
and  but  for  the  hchen,  they  could  never  have  grown  here 
at  all. 

Lichens,  as  we  have  said,  are  able  to  eat  into  the  rock, 
as  oxygen  eats  into  iron,  and  by  similar  means,  for  both 
are  strongly  acid;  and  on  removing  lichens  from  a  stone 
one  sees  indentations  similar  to  those  left  on  a  piece  of 
iron  by  the  removal  of  rust.  But  what  is  true  of  lichens 
is  true  in  a  degree  of  all  plants.  The  roots  of  all  plants, 
that  is  to  say,  are  acid,  though  in  a  less  degree,  especially 
the  young,  fine,  hair-like  roots;  and  if  these  find  their  way 
through  the  thin  soil  to  the  rock  beneath,  they  eat  into  it, 
leaving  a  distinct  impression  of  themselves  upon  it  when 
they  are  removed.     The  finest  hair  will  leave  its  mark. 

But  roots  also  exert  a  powerful  influence  upon  the 
rocks  in  another  way.  A  very  common  method  of  break- 
ing up  the  rocks  in  use  with  quarrymen  is  to  drive  into 
them  plugs  of  very  dry  wood.  These  plugs  are  then 
watered,  whereupon  they  swell  with  such  force  as  to  spht 
even  the  hardest  granite.  Roots  act  in  a  similar  manner, 
though  less  violently;  and  by  swelhng  in  every  direction, 
they  gradually  widen  any  cracks  into  which  they  have 
found  their  way,  and  actually  wedge  off  large  slices  from 
the  sides  of  hills  and  cliffs. 

In  the  neighborhood  of  Mount  Etna  people  make  the 
roots  of  the  prickly-pear  work  for  them  in  this  way,  for 
they  want  to  hasten  the  breaking  up  of  the  lava,  in  order 
that  they  may  turn  it  to  account  as  soon  as  possible.  The 
lava  cracks  as  it  cools,  and  in  every  crevice  that  appears 
they  insert  a  branch  of  this  cactus,  which  not  only  lives, 
but  soon  begins  to  grow,  thanks  to  the  warmth,  sunshine, 
and  moisture  of  the  genial  climate.     Its  roots  cannot,  of 


Soil-Makers  29 

course,  penetrate  the  lava,  but  they  can  and  do  make 
their  way  into  every  crack  and  cranny  within  reach,  and 
as  they  grow  and  swell  they  break  up  the  rock  into  frag- 
ments. 

As  to  what  the  plant  hves  upon  in  the  absence  of  soil, 
it  must  be  remembered  that  often  a  very  little  mineral 
food  is  enough  for  a  plant,  if  only  it  is  able  to  make  the 
most  of  what  there  is  and  has  plenty  of  water;  then  we 
must  remember,  too,  that  lava  is  especially  rich  in  the 
materials  required  by  plants,  and  that  water  flowing  over 
it,  or  draining  through  it,  would  certainly  dissolve  some 
of  these  materials  and  bring  them  within  reach  of  the 
roots,  which  would  obtain  them  in  this  way  quite  as  well 
as  from  soil. 

But  we  have  now  to  consider  other  means  by  which 
nature  prepares  the  soil.  Hitherto  we  have  confined  our 
attention  to  what  is  done  with  the  rocks  on  the  spot,  the 
soil  being  left  where  it  is  made;  but  this  proceeding  is 
attended  by  certain  disadvantages:  the  soil  rarely  attains 
any  great  depth,  for  one  thing,  as  the  rock  below  is  pro- 
tected more  or  less  from  frost;  and  then,  again,  generally 
speaking,  one  kind  of  rock  alone  does  not  contain  all  that 
is  necessary  to  make  a  really  fertile  soil  rich  in  all  the 
various  mineral  matter  required  for  luxuriant  crops.  If 
we  look  at  those  soils  which  are  acknowledged  to  be  the 
richest  in  the  world  we  shall  find  that,  as  a  rule,  they  have 
been  much  mixed.  We  say  as  a  rule,  because  most  of 
the  lavas  are  rich  enough  in  the  minerals  which  plants 
require,  and  are  also  so  well  drained,  thanks  to  the  cracks 
and  fissures  within,  that  they  do  form  most  productive  soil 
when  simply  crumbled  down. 

With  the  granites,  however,  the  case  is  very  different: 


30  The  Great  World's  Farm 

they  are  poor  in  the  necessary  minerals  to  begin  with,  and 
what  they  do  possess  is,  as  we  have  seen,  dissolved,  and 
in  great  part  washed  away.  Granite  slopes  are  poor  and 
sandy,  therefore,  while  the  clay  deposited  at  their  feet  is 
too  stiff  and  compact  to  be  fertile;  and  nature  seems  to 
tell  the  farmer  as  plainly  as  she  can  that  in  most  cases  he 
will  not  find  it  worth  his  while  to  try  and  grow  wheat 
either  on  the  hills  or  in  the  dales  of  a  granite  district.  Of 
course,  where  granite  decays  on  the  level,  and  its  various 
minerals  remain,  all  crumbled  down  and  mixed  together,  it 
is  naturally  more  fertile  than  where  the  best  of  them  are 
washed  away;  and  thus  we  find  that  the  granite  soils  of 
the  Scilly  Isle  are  far  more  productive  than  those  of  the 
Scotch  hills,  and  are  capable  of  bearing  good  crops  of 
corn,  in  part  at  least,  because  less  of  the  potash  has  been 
washed  away  from  them.  But  some  thanks  are  also  due 
to  the  more  genial  climate,  for  on  the  granite  highlands  of 
Dartmoor  there  is  no  vegetation  but  heath  and  coarse 
grass,  and  though  one  has  heard  of  laborers  attempting  to 
cultivate  portions,  and  not  without  some  success,  it  is 
impossible  to  say  that  the  soil  is  naturally  adapted  for 
either  field  or  garden  crops.  The  moor  is  flat  enough, 
indeed,  to  prevent  the  separation  of  the  sand  and  clay, 
and  such  minerals  as  the  granite  possesses  are  fairly  enough 
mixed  without  much  loss  by  washing;  but  the  natural 
poverty  of  the  rock  is  aggravated  by  its  elevated  situation 
on  the  one  hand,  and  by  the  shallowness  of  the  soil  on  the 
other,  and  the  soil  therefore  labors  under  the  two  great 
disadvantages  of  a  cold  climate  and  want  of  drainage. 
To  the  latter  of  these  are  due  the  many  bogs  which  abound, 
not  only  on  Dartmoor,  but  on  the  granites  of  Scotland, 
and  the  serpentine  rocks  of  the  Lizard  as  well. 


Soil-Makers  31 

The  soil  of  the  chalk  downs  is  hke  that  of  the  granite 
table-lands  in  one  respect,  that  it  is  derived  chiefly  from 
the  rock  beneath,  and  has  had  little  advantage  of  inter- 
mixture with  others;  but — and  this  makes  a  vast  differ- 
ence— the  underlying  chalk  absorbs  water  readily,  like  a 
sponge,  so  that  bogs  have  no  chance  of  forming.  The 
downs  grow  excellent  pasture,  and  are  especially  adapted 
for  sheep-farming;  but  if  people  will  plow  up  the  soft  fine 
herbage  of  nature's  providing  and  try  to  grow  corn  and 
turnips  instead,  they  must  not  be  surprised  if  they  get 
poor  crops  in  return  for  much  labor. 

Most  of  the  richest  soils  of  the  world  have  been  mixed, 
either  by  the  work  of  rivers,  or  by  that  of  other  laborers 
to  be  considered  by  and  by.  And  besides  being  mixed, 
they  have  in  many  cases  been  transported  from  situations 
where  they  were  comparatively  useless,  to  others  where 
their  good  qualities  can  be  turned  to  the  best  account. 

The  richest  soil  in  the  world  is  of  little  use  on  a  lofty 
mountaintop,  for  none  but  lowly  plants  can  stand  the  cold 
and  exposure,  and  anything  to  be  called  luxuriant  vege- 
tation is  impossible. 

But  in  numberless  instances  soil  has  been  brought 
down  from  the  mountains,  where  it  must  have  been  com- 
paratively unproductive;  it  has  been  mixed  and  prepared, 
and  finally  spread  out  in  extensive  fields  ready  made  to  the 
farmer's  hand,  in  situations  where  his  crops  can  have  the 
warmth  and  moisture  which  are  essential  to  them. 

It  certainly  does  appear  perverse,  therefore,  that  men 
should  persist  in  trying  to  grow  crops  where  they  seem 
plainly  meant  to  feed  their  sheep;  and  that  they  should 
want  to  plow  up  moors  and  deer-forests  which  could  never 
make  productive  fields,  when  by  long  and  most  elaborate 


32  The  Great  World's  Farm 

preparation  thousands  and  millions  of  acres  have  been 
provided  which  would  yield  abundant  harvests  with  less 
than  half  the  labor. 


QUESTIONS  FOR  REVIEW 

1.  Describe  the  earliest  forms  of  vegetation  which  are  found 
upon  rocks. 

2.  How  do  these  lichens  receive  nourishment? 

3.  Show  the  steps  by  which  soil  accumulates  upon  the  rock. 

4.  By  what  different  means  do  roots  break  up  the  rocks? 

5.  Why  is  the  soil  of  a  granite  district  apt  to  be  poor? 

6.  Explain  the  difference  between  the  granite  soil  of  the 
Scilly  Islands  and  of  Dartmoor. 

7.  What  is  the  character  of  the  soil  of  the  chalk  downs, 
and  why? 

8.  What  process  is  necessary  before  a  soil   can  be  very 
fertile? 


CHAPTER  IV 

SOIL-CARRIERS 

We  have  now  seen  by  what  means  the  rocks  are 
crumbled  down;  but  in  many  cases  much  besides  crum- 
bhng  is  necessary  to  convert  rock  into  good  soil.  Nearly 
ail  the  soils  which  we  look  upon  as  especially  fertile  have 
been  made  so  by  being  mixed. 

When  we  consider  which  are  the  best  corn-producing 
regions  of  the  earth,  our  thoughts  naturally  turn  first  to 
Egypt,  once  the  granary  of  the  world. 

And  what  is  Egypt?  "The  gift  of  the  Nile,"  as  the 
ancient  historian  says.  The  soil  which  produces  such 
wonderful  crops  has  not  been  produced  by  the  decay  of 
the  rocks  upon  which  it  rests,  but  is  a  mixture  of  soils 
.  brought  in  great  part  from  the  lofty  mountains  of  Abys- 
sinia, hundreds  of  miles  away.  The  only  fertile  tracts  in 
Abyssinia  itself  are  due  to  the  sediment  washed  down 
from  these  mountains,  which  are  rich  in  the  minerals  most 
desired  by  plants,  but  like  the  Cheviot  Hills  already  men- 
tioned, unproductive,  owing  to  their  height  and  the  con- 
sequently severe  climate. 

The  top  of  this  magnificent  chain  of  mountains  is  a 
vast  table-land,  upon  which  the  rains  descend  heavily  and 
incessantly  during  some  three  or  four  months  of  the  year, 
the  fall  being  so  abundant  as  to  supply  five  tremendous 
mountain-torrents,  which  rush  down  the  sides  of  the 
mountains  with  the   force  of  cataracts,  and  carry  with 

33 


34  The  Great  World's  Farm 

them  enormous  quantities  of  rock,  which  is  ground  up  bv 
degrees  into  the  finest  mud  and  poured  into  the  Nile.  So 
large  is  the  amount  of  sediment  brought  down  by  the 
river — which  those  who  like  statistics  may  be  interested  to 
know  is  about  equal  in  bulk  to  a  solid  cube  measuring 
more  than  five  feet  each  way  transported  in  every  second — 
that  the  river-bed  is  gradually  rising,  and  the  inundation 
therefore  extends  further  and  further;  and  very,  very 
slowly,  but  still  surely,  more  of  the  desert  is  being  con- 
verted into  fruitful  soil.  Left  upon  the  Abyssinian  Moun- 
tains, the  materials  of  which  this  sediment  is  composed 
would  have  had  little  or  no  value — for  man's  purposes,  ai 
least — but  transported  to  the  magnificent  climate  of 
Egypt,  and  mixed  with  other  matter,  they  form  a  soil 
which  is  the  very  perfection  of  fertility. 

The  sediment  is  not  all  deposited  on  the  land  or  in  the 
river-bed,  however;  much  is  carried  into  the  Mediterra- 
nean, where  another  delta  is  being  gradually  formed,  equal 
no  doubt  to  the  old  one  in  richness,  and  capable  of  bear- 
ing crops  as  abundant,  should  it  ever  rise  above  the  waters.. 
A  delta  is  possible  only  where  there  is  little  or  no  tide,  or 
current,  to  carry  the  sediment  away. 

But  it  must  not  be  forgotten  that  something  more  has 
been  done  than  merely  to  transport  this  wonderful  soil. 
It  has  also  undergone  much  mixing,  and  consists  not  only 
of  mud  washed  from  the  Abyssinian  Mountains,  but  of 
sand,  which  is  blown  into  the  river  in  vast  clouds  from  the 
desert.  The  Nile  itself,  too,  has  done  a  great  deal  of 
grinding,  and  sand  and  miud  making,  as  well  as  its  tribu- 
taries. Sand,  driven  by  water,  will  wear  away  the  hardest 
rock  by  degrees;  and  by  means  of  the  sand  which  the 
wind  blows  into  it,  the  river  has  cut  its  way  through  the 


Soil-Carriers 


35 


rocks,  scooping  out  for  itself  a  wide,  deep  bed.  The  solid 
mass  of  rock  thus  removed,  grain  by  grain,  has  also  con- 
tributed in  no  small  degree  towards  the  formation  of  the 
Great  Delta. 

But  even  this  is  not  all.  No  soil  can  be  really  fertile, 
however  rich  in  mineral  matter,  unless  it  contain  some 
amount  of  animal  or  vegetable  matter.  And  this,  too, 
has  been  supplied  to  the  Delta  in  an  interesting  and 
remarkable  way. 

Nile  water,  like  that  of  all  rivers  more  or  less,  con- 
tains a  vast  number  of  microscopic  animals  and  vegetables, 
the  lowest  and  simplest  forms  of  life,  which  are  not  only 
left  behind  with  the  mud,  but  are  killed  in  myriads  where 
they  come  in  contact  with  salt  water.  The  Mediterranean 
being  a  tideless  sea,  this  wholesale  destruction  cannot  take 
place  except  at  the  mouth  of  the  river,  and  for  a  certain 
distance  beyond  it  in  the  sea.  Fresh  water  being  hghter 
than  salt,  flows  over  the  latter  at  first,  before  the  two 
mingle;  and  as  sea  water  abounds  in  these  minute  forms 
of  life  to  a  much  greater  extent  than  river  water  does,  and 
as  fresh  water  is  as  deadly  to  the  one  as  salt  to  the  other, 
the  destruction  wherever  the  two  come  in  contact  must  be 
wholesale. 

But  where  rivers  are  affected  by  the  tide,  there  the  salt 
water  flows  up  under  the  fresh,  for  many  a  mile  above 
their  mouths,  carrying  with  it  a  living  freight,  which  must, 
to  a  large  extent,  perish  and  be  left  behind;  while  the 
microscopic  inhabitants  of  the  river  water  are  destroyed 
with  equal  certainty  wherever  they  come  in  contact  with 
that  which  is  salt,  or  even  brackish;  that  is,  partially  salt. 

The  whole  of  southern  Louisiana,  with  its  extensive 
cotton  and  rice  fields,  was  made  in  hke  manner  by  the 


;^6  The  Great  World's  Farm 

Mississippi,  which  becomes  a  dense  yellow  torrent  after  it 
is  joined  by  the  Missouri,  and  brings  down  with  it  a  heavy 
load  of  mud,  ground  from  mountains  three  thousand  miles 
away,  which  it  has  deposited  in  som.e  places  to  a  depth  of 
three  hundred  feet. 

And  so  again,  on  a  smaller  scale,  the  low  plain  at  the 
head  of  the  Lake  of  Geneva  is  formed  of  mud  from  the 
mountains,  which  the  Rhone  has  brought  down  and  de- 
posited in  the  lake,  adding  to  it  year  by  year,  until  it  has 
risen  above  the  water,  and  Port  Vallais,  which  stood  on 
the  margin  of  the  lake  in  Roman  times,  now  lies  a  mile 
and  a  half  inland. 

Inundations  are  caused  usually  either  by  excessive  rain, 
such  as  that  which  falls  periodically  in  Abyssinia,  or  by 
the  mehing  of  the  snow  in  spring;  but  passing  mention 
must  here  be  made  of  certain  inundations  brought  about 
by  very  different  causes,  namely,  the  work  of  the  beaver. 
This  animal,  though  it  stih  inhabits  the  north  of  Europe 
and  Asia,  is  nowhere  now  so  plentiful  as  in  North  America, 
where,  also,  the  effect  of  its  work  in  the  past  may  best  be 
observed. 

But  the  beaver  once  abounded  in  England  and  Wales, 
and  indeed  throughout  the  greater  part  of  Europe,  as  the 
names  of  many  places,  such  as  Beverley,  Beverstone, 
Biverbike,  and  many  others,  plainly  show.  What  we  see 
of  its  work  in  America,  therefore,  is  probably  only  a  speci- 
men of  v/hat  it  has  done  wherever  it  has  been  undisturbed. 
Here,  at  all  events,  thousands  of  acres  of  land  have  been 
submerged,  at  one  time  and  another,  as  the  result  of  its 
labors.  As  is  well  known,  the  beaver  is  in  the  habit  of 
building  dams;  and  these  are  often  so  solid  and  extensive 
as  to  stop  up  the  streams  and  rivers  in  which  they  are 


Soil-Carriers  oy 

constructed,  causing  them  to  overflow  and  form  shallow 
lakes. 

But  local  floods  were  only  the  first  result  of  its  work; 
for  the  streams  brought  down  with  them  the  usual  sedi- 
ment, which  was  spread  over  the  inundated  surface, 
gradually  raising  its  level,  until  the  lake  became  a  marsh 
covered  with  marsh-plants.  Then,  as  the  sediment  still 
accumulated,  the  marsh-plants  by  degrees  found  the  situ- 
ation too  dry  for  them,  and  died  off;  their  places  were 
then  taken  by  grasses,  and  the  lakes  were  thus  converted 
into  meadow-land,  fertile,  as  river-formed  soils  usually 
are,  and  enriched  by  the  decay  of  the  marsh  plants. 

Rivers,  then,  must  be  reckoned  among  the  most  impor- 
tant makers  and  carriers  of  soil.  But  the  wind,  too,  does 
much  good  service,  though  also  occasional  damage,  from 
man's  point  of  view,  as  nature's  laborers  are  apt  to  do,  in 
these  disorganized  days. 

On  the  Lincolnshire  Wolds,  for  instance,  and  on  the 
coast  of  Norfolk,  where  the  soils  are  light  and  sandy,  the 
whole  of  the  finer  portion,  as  well  as  the  seed  sown,  is 
sometimes  altogether  blown  away  by  the  equinoctial  gales. 
One  field  near  Cromer  was  sown  three  times  in  the  course 
of  a  single  spring,  and  was  finally  left  to  itself,  all  the 
upper  portion  of  the  soil  being  banked,  hke  a  snow-drift, 
against  the  hedge. 

But  for  the  hedges  the  wind  would  no  doubt  have 
spread  the  soil  fairly  over  the  neighboring  fields.  Its 
efforts  on  this  occasion  were,  however,  certainly  mis- 
directed. 

As  to  the  enormous  distances  which  fine  dust  is  often 
carried,  we  have  positive  proof  in  the  brick-red  or  cinna- 
mon-colored sirocco  dust  which  falls  thickly  upon  vessels 


38  The  Great  World's  Farm 

in  the  Atlantic  at  certain  seasons  of  the  year,  and  is 
carried  to  Europe  as  far  inland  as  the  Tyrol.  This  dust, 
which  is  exceedingly  fine,  has  traveled  thousands  of  miles 
on  the  wings  of  the  wind,  the  greater  part  of  it  having 
been  borne  across  the  Atlantic  from  the  banks  of  the 
Orinoco  and  Amazons.  Its  value  as  a  fertilizer  is  recog- 
nized by  the  North  American  farmers,  who  use  a  similar 
deposit  of  "flint-earth"  to  mix  with  some  of  their  heavy 
soils.  Very  fertilizing  also  must  be  the  volcanic  dust, 
which,  being  carried  high  up  into  the  air,  at  times  prob- 
ably far  above  the  cloud-region,  is  conveyed  enormous 
distances  before  it  finally  sinks  to  the  earth. 

The  most  tremendous  volcanic  outburst  on  record  is 
that  of  Krakatoa  in  1883,  when  milhons  of  tons  of  matter 
were  hurled  into  the  upper  air,  and  dust,  to  the  depth  of 
two  inches,  fell  a  thousand  miles  off.  The  vegetation  of 
the  neighborhood  w^as,  of  course,  utterly  destroyed,  but 
in  this  instance  it  took  less  than  five  years  to  cover  up  the 
dismal  scene  of  desolation  with  a  fresh  growth  of  tropical 
luxuriance.  Just  so  Vesuvius  is  said  to  smother  and 
destroy  the  crops  in  its  neighborhood  every  eighth  year; 
but  it  is  this  very  fact  which  makes  the  soil  so  wondrously 
fertile  during  the  other  seven. 

However,  we  are  concerned  just  now  chiefly  with  the 
work  done  by  the  wind,  and  must  glance  at  one  curiously 
interesting  sample  of  it  which  has  been  observed  in  the 
valley  of  the  Limagne,  in  Auvergne.  Here  there  is  no 
active  volcano  to  furnish  dust,  and  yet  the  fields  seem  to 
get  it — and  that,  too,  without  the  drawback  of  being 
suffocated  every  few  years.     Where  does  it  come   from.? 

The  wind  blows  chiefly  from  the  west  and  southwest,, 
across  the  mountain-chain  of  the  Domes.     The  air  on  the 


Soil-Carriers  39 

western  side  of  the  mountains  is  bright  and  clear,  but  that 
on  the  Limagne  side  is  generally  slightly  hazy,  and  the 
haze  seems  to  consist  of  fine  dust.  And  when  we  inquire 
about  the  mountains,  we  find  that  they  are  extinct  vol- 
canoes, and  are  widely  strewn  with  volcanic  ashes,  the 
relics  of  ancient  eruptions,  rich  in  the  minerals  which 
make  the  most  fertile  soils,  and  just  in  the  condition  in 
which  plants  can  most  readily  make  use  of  them. 


QUESTIONS  FOR  REVIEW 

1.  Describe  the  various  ways  by  which  the  soil  of  Egypt  is 
made  extraordinarily  fertile. 

2,  What  important  part  does  the  beaver  play  in  the  work 
of  soil  distribution? 

3.  Give  examples  of  the  work  of  the  wind  in  scattering  soil. 

4,  What  curious  condition  of  wind  and  soil  exists  in  the 
valley  of  the  Limagne? 


CHAPTER  V 

SOIL-BINDERS 

The  materials  being  ground  up,  mixed,  and  in  some 
cases  transported,  there  are  still  important  matters  to  be 
attended  to  before  anything  strictly  to  be  called  "soil" 
can  be  formed. 

The  first  thing  is  to  make  the  future  soil  settle  down, 
since  nothing  of  value  can  grow  in  a  wandering  sand-drift. 
The  deposits,  whatever  they  be,  need  protection  against 
the  washing  of  the  rain  and  the  drying  of  the  wind,  which 
will  not  only  dry  the  surface,  but  blow  it  away  in  clouds 
if  it  is  left  exposed. 

Even  to  this  day  the  plains  of  Hungary  suffer  from 
dust-storms,  though  they  have  long  been  covered  with 
vegetation;  and  we  may  easily  imagine  how  much  worse 
these  must  have  been  when  sun  and  wind  had  full  play, 
with  nothing  to  check  them. 

It  is  clear,  too,  that  where  sand  or  volcanic  ashes  have 
been  brought  by  the  wind,  the  same  wind  may  in  many 
instances  scatter  them  again.  And  where  mud  has  been 
brought  down  by  a  river  and  deposited  within  reach  of  the 
tide,  there  it  will  be  liable  to  be  washed  away,  unless  some 
means  be  taken  to  fix  it  to  the  spot. 

Let  us  even  look,  for  instance,  at  a  railway  embank- 
ment. It  has  been  piled  by  human  hands  with  a  special 
object,  and  is  a  far  more  solid  mass  than  if  it  had  been 
merely  blown  together;  but  yet  it  to  some  extent  wastes 

40 


Soil-Binders  41 

away.  Its  bare,  exposed  surface  is  washed  and  wasted  by 
the  rain,  dried  and  blown  away  by  the  wind;  for  there  is 
nothing"  to  protect  it  from  either,  to  begin  with.  But  this 
state  of  things  does  not  last  long.  There  is  always  plenty 
of  seed  floating  in  the  air,  ready  to  sow  itself  on  any  bare 
space  it  can  find;  so  that  in  two  or  three  years'  time  the 
embankment  is  overgrown  with  grass,  whose  roots  are  so 
matted  together  that  further  shifting  of  the  soil  is  to  a 
large  extent  prevented. 

Of  course,  where  seed  is  sown  even  before  the  soil  is 
made,  as  we  have  seen  in  the  case  of  lichens,  there  the 
mold  as  it  is  formed  is  kept  in  place  and  protected,  and  is 
able  to  deepen  undisturbed.  But  where  sand  has  been 
heaped  together  by  the  wind,  or  mud  deposited  on  the 
coast,  there  something  is  needed  to  give  it  firmness,  or 
else  it  will  be  dispersed  again. 

The  sandhills  on  the  plains  of  Venezuela,  for  example, 
are  still  constantly  moving  to  and  fro,  here  to-day  and 
there  to-morrow,  except  in  one  district,  where  they  have 
been  consolidated  into  a  low  range  of  permanent  hills 
by  a  curious  grass  with  tall,  cutting,  sword-edged  blades, 
which  grows  so  closely  and  with  such  rapidity  that  any 
paths  made  by  travelers  are  quite  covered  up  and  destroyed 
by  it  in  a  few  days. 

The  plants  which  are  most  useful  for  this  work  of  bind- 
ing the  soil  and  giving  it  its  first  firmness  are  those  which, 
besides  growing  quickly,  also  send  out  especially  long 
roots,  runners,  or  underground  stems,  often  miscalled 
roots,  which  are  pegged  down  at  frequent  intervals  by  real 
roots,  much  in  the  same  way  as  the  thatcher  binds  down 
the  straw  on  the  rick-top.  The  couch-grass  and  others 
have  long  underground  stems  of  this  sort,  as  the  gardener 


/j.2  The  Great  World's  Farm 

knows  to  his  sorrow;  and  then  there  are  the  bindweeds, 
most  appropriately  so  named,  for  they  send  out  long, 
trailing  runners  above  ground,  having  roots  at  each  joint, 
which  make  them  extremely  difficult  to  get  rid  of  when 
once  they  have  established  themselves  in  a  garden.  Their 
tropical  relatives,  the  ipoma^as — plants  of  much  larger 
growth,  but  bearing  similar  convolvulus-blossoms  of  more 
brilliant  color — are  among  the  plants  which  render  most 
useful  service  in  the  Bermudas  by  stopping  the  fine  white 
coral-sand  of  the  coast  from  invading  and  burying  the 
neighboring  gardens. 

When  the  sand  has  been  consolidated  and  improved  by 
the  growth  and  decay  of  these  and  similar  plants,  there 
follow  shrubs  and  small  trees,  such  as  do  not  object  to  the 
saltness  of  the  soil;  and  finally,  when  the  way  has  been 
carefully  prepared,  the  once  barren  sand-banks  are  covered 
with  groves  of  coco-palms.  It  is  a  fact  never  to  be  lost 
sight  of,  that  here,  as  so  frequently  elsewhere,  the  first 
all-important  work  is  done  by  comparatively  feeble  instru- 
ments; the  dust-like  lichen  prepares  the  way  for  the  pine, 
and  the  insignificant  salt-worts,  and  weak-stemmed,  creep- 
ing bindweeds  make  ready  for  the  palm. 

The  mangrove,  like  the  coco-palm,  thrives  in  salt  water, 
but  is  unlike  it  in  being  able  to  grow  without  any  prepa- 
ration, and  itself  does  much  to  consofidate  the  mud  in 
which  it  grows.  It  is  found  on  many  tropical  coasts, 
growing  between  high  and  low  water  mark,  and  in  river 
estuaries  washed  by  the  sea  during  one  part  of  the  day, 
and  left  exposed  during  another.  From  its  branches  it 
sends  down  long  roots  which,  on  reaching  the  mud,  fix 
themselves  firmly  in  it,  and  become  independent  trees; 
and  the  seed,  which  begins  to  germinate  and  grow  while 


Soil-Binders  43 

still  in  the  fruit  and  on  the  bough,  also  sends  out  branches 
and  roots,  sometimes  long  enough  to  touch  the  ground, 
before  it  falls.  The  fruit-roots,  branch-roots,  and 
stems,  together  form  a  tough,  closely  woven  network, 
in  which  the  mud  of  the  river  is  caught  and  entangled, 
and  converted  into  soHd,  or  something  like  sohd,  land, 
very  much  more  quickly  than  it  would  be  without  their 
help. 

In  Holland  the  people  have  taken  a  leaf  out  of  nature's 
book,  and  carefully  plant  the  sea-dikes,  on  which  the  very 
existence  of  their  land  depends,  with  the  ''sharp  rush," 
whose  multitude  of  roots  mat  together  near  the  surface, 
besides  striking  deep  into  the  soil. 

The  growth  of  the  sea-reed  is  even  more  remarkable. 
It  will  grow  in  the  very  driest  soil,  and  has  been  planted 
in  the  Hebrides  to  cure  sand-drift.  Its  runners  are  often 
as  much  as  twenty  feet  long,  and  so  tough  and  strong 
that  they  have  been  used  for  rope-making. 

Some  quite  fragile-looking  roots  are  indeed  remarkably 
tough,  and  capable  of  resisting  an  immense  strain  without 
breaking.  The  roots  of  the  Lucerne  clover  are  said  to  be 
often  as  strong  as  those  of  an  ash-tree,  though,  of  course, 
very  much  finer,  and  looking  much  weaker;  and  they  have 
at  times  given  unmistakable  proof  of  their  strength,  not 
merely  by  resisting  the  advance  of  the  plowshare,  but  by 
actually  breaking  it. 

On  mountain  slopes,  too,  the  roots  of  trees  and  brush- 
wood serve  to  keep  in  its  place  the  soil  which  must  else 
slip  down  by  its  own  weight,  even  if  there  were  no  rain  to 
wash  or  wind  to  blow  it.  And  where  people  have  been 
so  short-sighted  as  to  cut  down  mountain  forests,  there 
they  have   had  to   lament  not   merely  the  ruin,   but  the 


44  The  Great  World's  Farm 

actual  loss,  of  the  fields  in  their  vicinity,  which  have  been 
carried  bodily  away. 

In  some  parts  of  the  French  Alps  half  the  cultivated 
ground  has  been  washed  away,  owing  to  the  reckless 
destruction  of  the  pines;  and  this  is  not  all,  for  when  the 
forests  are  gone,  not  only  does  the  soil  follow,  but  so  do 
the  avalanches;  or  rather  they  come!  plunging  down 
from  the  heights  above  and  overwhelming  everything  in 
their  way.  The  trees,  and  the  trees  only,  were  strong 
enough  to  resist  them. 

It  is  remarkable  what  a  very  slight  obstacle  is  often 
enough  to  stop  the  onward  motion  of  a  sand-drift,  a  few 
oleanders,  by  no  means  very  sturdy  shrubs,  being  often 
found  sufficient  for  the  purpose  in  the  Bermudas. 

In  the  wide  plains  of  South  Hungary,  where  the  wind 
has  nothing  to  break  its  force,  the  railway  lines  are  often 
in  winter  blocked  with  snowdrifts,  which  there  seemed  to 
be  no  means  of  preventing,  until  in  one  part  the  experi- 
ment was  tried  of  planting  hedges  of  Pronins  roses  on 
each  side.  The  hedges  are  of  the  height  of  a  tall  man, 
and  the  lines  were  kept  clear  during  some  exceptionally 
heavy  falls  of  snow  a  few  years  ago  where  they  were 
invariably  blocked  before. 

On  the  southwest  coast  of  France  there  is  an  extensive 
sandy  region  known  as  the  Landes,  which  at  one  time 
seemed  likely  to  be  converted  into  a  veritable  Sahara,  and 
was  saved  from  this  fate  by  nothing  else  but  the  planting 
of  pines. 

In  the  last  century  the  sand-dunes  were  always  in 
motion,  constantly  changing  their  places,  ebbing  and  flow- 
ing hke  the  tide,  but  creeping  gradually  further  and  further 
inland.     When   the   storm-wind   blew  from   the  west  it 


Soil-Binders  4^ 

caught  up  the  sand  and  scattered  it  over  the  adjacent 
country,  where  it  fell  like  volcanic  ashes,  doing  equal  dam- 
age and  none  of  the  good,  for  it  consists  to  a  large  extent 
of  fine  white  quartz,  the  most  hopelessly  barren  sand  there 
is. 

In  ancient  times  this  district  is  said  to  have  been  fairly 
well  covered  with  oak  woods,  remains  of  which  are  yet  to 
be  seen;  why  and  when  they  were  destroyed  seems  to 
be  unknown,  but  the  results  were  disastrous,  and  even 
alarming.  At  length,  however,  the  happy  thought  came 
to  an  engineer  named  Bremontier,  in  1787,  that  where 
trees  had  grown,  trees  might  be  induced  to  grow  again, 
and  the  attempt  was  made,  not  with  oaks,  for  they  could 
not  have  borne  the  sand,  but  with  the  maritime  pine. 
Over  and  over  again  it  was  tried  and  failed,  owing  to  the 
shiftiness  of  the  sand;  but  at  length,  by  dint  of  immense 
perseverance,  the  seed  was  induced  to  take  root,  and  then 
the  worst  of  the  battle  was  over. 

One  dune  after  another  was  brought  to  a  standstill, 
and  that  which  threatened  to  become  a  desert  has  gradu- 
ally been  converted  into  profitable  pine-woods,  with  inter- 
mediate stretches  of  vigorous  heather  and  furze  ten  feet 
high,  and  here  and  there  a  thick  growth  of  hawthorn  and 
holly. 

We  may  conclude  this  chapter  by  mentioning  the  curi- 
ous origin  ascribed  to  certain  patches  of  grass  which  occur 
frequently  all  over  the  bison  region  of  North  America. 
These  patches  are  said  to  be  evidently  due  to  the  bison's 
habit  of  wallowing  in  the  dust,  and  were,  in  fact,  the 
wallowing  places  of  the  herd.  The  repeated  wallowing 
of  a  number  of  animals  created  shallow  hollows  or  depres- 
sions which  the  rain  converted  into  pools,  where  the  water 


46  The  Great  World's  Farm 

lingered  and  into  which  it  drained  from  the  surrounding 
soil.  Even  when  the  water  had  drained  away  the  hollows 
would  continue  damp  for  some  time,  and  grass-seeds  fall- 
ing upon  them  would  readily  spring  up.  The  grass-plants 
would  speedily  weave  a  network  of  roots  over  the  whole, 
forming  in  time  a  thick  mat  by  which  the  soil  would  be 
effectually  held  together  and  consolidated,  and  the  bison 
who  wanted  a  dust  bath  in  future  would  have  to  choose  a 
fresh  wallowing  place  for  himself  and  his  companions. 

QUESTIONS  FOR  REVIEW 

1.  Describe  some  of  the  plants  which  serve  as  soil-binders. 

2.  What  peculiar  qualities  has  the  mangrove? 

3.  Give  instances  of  the  strength  of  these  soil-binders. 

4.  What   result  has   often    followed  the   cutting   down   of 
mountain  forests? 

5.  What   expedients   have   been  used    for  checking   both 
snow  and  sand  drifts? 

6.  Describe  the  growth  of  grass  in  the  bison  country. 


I 


I 


CHAPTER  VI 

FIELD-LABORERS 

The  field-laborers  whose  work  we  are  going  first  to 
look  at  are  somewhat  rough  in  their  ways,  it  must  be 
confessed,  and  not  such  as  the  farmer  generally  cares  to 
see  at  work  upon  his  land.  For  when  he  has  taken  pos- 
session of  the  beds  of  soft  earth  ready  prepared  for  him, 
his  plows  and  harrows  come  in  very  usefully,  and  he  is  of 
opinion  that  he  can  manage  the  tillage  of  his  fields  himself. 

Nature,  however,  has  no  steel  plows,  and  her  fields  must 
be  tilled  by  other  means,  for  they  need  it  as  well  as  the 
farmer's.  And  her  laborers  work  in  all  parts  of  the  farm, 
giving  man  a  vast  amount  of  help,  for  which  he  is  often 
not  as  grateful  as  he  might  be,  for  he  and  they  do  not  at 
present  understand  one  another;  and  though  he  may  tame 
a  lion  he  cannot  control  a  worm. 

No  soil  is  really  fertile,  whatever  the  mineral  matter 
composing  it,  unless  it  also  contain  some  amount  of 
organic  matter — matter  derived  from  organized,  living 
things,  whether  animal  or  vegetable.  Organic  matter 
alone, is  not  enough  to  make  a  fertile  soil;  but  with  less 
than  one-half  per  cent  of  organic  matter,  no  soil  can  be 
cultivated  to  much  purpose.  Even  with  this  quantity  it 
will  not  grow  corn  of  any  kind  successfully,  but  it  will 
grow  wild  crops  with  less;  and  these  in  time  add  what  is 
required,  if  they  are  let  alone  for  many  generations.  The 
black  earth  of  Russia,  which  is  jet  black  when  wet  and 

47 


48  The  Great  World's  Farm 

brown  when  dry,  owes  its  color  and  much  of  its  fertihty 
to  the  finely  divided  and  well-mixed  vegetable  matter 
which  it  contains,  the  remains  of  countless  generations  of 
wild  plants,  which  held  undisturbed  possession  there  for 
ages,  but  have  now  made  way  for  their  betters. 

All  soils  contain  some  amount  of  organic  matter,  animal 
or  vegetable,  but  chiefly  vegetable;  and  this  is  true  even 
of  such  as  seem  to  consist  only  of  sand,  clay,  or  chalk. 
For  wherever  it  is  possible  for  a  plant  to  grow  at  all, 
thither  something  suited  to  the  situation  is  sure  to  find  its 
way.  The  wild  crop  may  be  a  very  poor  one,  perhaps 
only  some  coarse,  wiry  kind  of  grass — for  there  is  hardly 
any  soil  so  poor  but  that  grass  of  some  kind  will  grow  in 
it — and  when  this  has  improved  the  soil  a  little,  other 
better  sorts  may  follow. 

But  it  is  the  effect  of  animal  life  that  we  are  now  to 
look  at.  Animals,  large  and  sniall,  benefit  the  land  by 
manuring  it;  but  this  is  so  obvious  a  benefit  that  we  need 
not  dwell  upon  it  further  than  to  remark  that  coprolites — 
the  fossilized  droppings  and  bones  of  animals  of  former 
ages — and  guano,  the  droppings  of  birds,  are  among  the 
most  valuable  manures  which  the  farmer  can  use,  and 
where  they  are  not  to  be  had  upon  the  spot  he  finds  it 
worth  his  while  to  bring  them  from  a  distance.  When, 
therefore,  we  consider  the  abundant  animal  life  which  for 
ages  occupied  many  of  the  lands  now  brought  under  the 
plow,  we  can  understand  one  cause  of  their  fertility — they 
have  been  regularly  manured  for  ages.  But  besides 
manuring  the  land  during  their  lives,  the  animals  must 
have  left  their  bones  to  enrich  it  also,  whenever  they 
escaped  being  devoured. 

Burrowing  animals  have  also  been  especially  useful  in 


Field-Laborers  49 

more  ways  than  one.  In  the  first  place,  they  have  added 
to  the  organic  matter  of  the  soil,  and  in  the  second,  to  the 
mineral  matter  also;  and  besides  this  they  have  done  much 
to  drain  the  soil,  and  expose  it  to  the  influences  of  the 
sun  and  air. 

The  organic  matter  which  they  have  added,  besides 
their  own  droppings,  consists  of  the  materials  which  they 
use  to  line  their  nests,  principally  leaves  and  grass,  and 
also  the  remnants  of  their  food,  nuts,  grain,  acorns,  and 
sometimes  the  whole  of  their  winter  stores. 

They  have  added  also  to  the  mineral  matter  of  the  soil 
by  helping  on  the  decay  of  the  underlying  rocks.  These 
are  seldom  at  any  great  depth  beneath,  for  the  loose 
materials  with  which  they  are  covered  are  but  as  a  film  of 
dust  compared  with  the  thickness  of  the  solid  mass.  The 
soil  at  its  very  thickest  is  measured  only  by  feet,  while 
the  solid  crust  of  the  earth  is  measured  at  least  by  hun- 
dreds of  miles;  and  in  most  cases  the  soil  is  actually  only 
a  few,  often  a  very  few,  feet  thick. 

In  the  western  regions  of  North  America,  from  Mexico 
to  the  Arctic  Ocean,  as  well  as  in  the  northern  parts  of 
the  Old  World,  there  are  a  large  number  of  small  animals 
called  by  the  general  name  of  ''ground-squirrels,"  and 
resembling  tree-squirrels  in  many  respects,  though  some 
of  their  habits  are  very  different.  Like  the  tree-squirrels, 
they  lay  up  stores  of  food,  but  unlike  them,  they  burrow 
in  the  ground,  and  live  together  in  large  villages  instead 
of  in  pairs. 

The  gopher,  or  Canada  pouched-rat,  too,  is  to  be 
found  in  the  prairie,  where  it  dwells  not  merely  in  thou- 
sands, but  in  hundreds  of  thousands,  and  has  so  completely 
taken,  perhaps  we  should  rather  say  kept,  possession  that 


50  The  Great  World's  Farm 

in  some  parts  other  quadrupeds  are  almost  excluded.  The 
gophers  extend  over  hundreds  of  thousands  of  square 
miles,  and  have  honey-combed  millions  of  acres.  One 
may  indeed  ride  for  days  and  even  weeks  through  some 
districts,  finding  them  everywhere  as  plentiful  as  if  the 
whole  district  were  one  vast  warren. 

Other  burrowers,  better  known  in  the  Old  World,  are 
the  marmots,  which  make  very  large  and  rather  compli- 
cated burrows,  and  have  quite  riddled  the  rocks  in  Turk- 
estan, in  some  parts  of  which  they  abound;  and  others 
again  of  the  same  great  family  of  rodents,  or  "gnawers," 
the  gerboas,  have  honey-combed  the  sides  of  mountains 
in  South  Africa,  and  possess  such  strong  teeth  that  in  the 
north  they  even  gnaw  through  the  thin  layer  of  stone 
beneath  the  sand,  and  thus  do  some  of  the  very  first  work 
of  the  pioneer  laborers. 

In  England  the  field  burrower  with  which  we  are  most 
familiar,  unpleasantly  familiar,  too,  is  the  common  mole. 
No  matter  where  he  lives,  the  mole's  labors  are  not  any- 
where looked  at  with  a  friendly  eye  by  farmer  or  gardener. 

The  sins  alleged  against  him  are:  that  he  drains  the 
soil  so  thoroughly  by  his  network  of  underground  galleries 
as  to  render  it  dry  and  barren ;  that  he  damages  the  crops 
by  uprooting  them,  and  by  exposing,  destroying,  or  eating 
their  roots;  and  finally,  that  he  uses  such  a  large  quantity 
of  spring  corn,  as  much  as  a  couple  of  hundred  blades,  to 
make  his  bed,  that  where  he  abounds  one-eighth  of  the 
crop  is  lost. 

These  are  serious  accusations;  but  the  mole  is  not 
without  friends,  enthusiastic  friends  even,  though  prob- 
ably not  farmers  or  gardeners,  and  these  declare  that  the 
damage  done  is  slight  .compared  with  the  service  rendered. 


Field- Laborers  c  i 

The  soil  is  greatly  benefited,  say  they,  by  being  upturned 
and  Hghtened ;  and  they  claim  that  the  mole  takes  high 
rank  among  nature's  field-laborers,  and  should  be  honored 
accordingly,  not  only  for  his  work  as  plowman,  but  also 
for  his  extraordinarily  large  and  voracious  appetite  for 
smaller  animals  of  all  sorts,  which  do  far  more  injury  to 
the  crops  than  himself. 

Wherever  a  mole  lives  the  organic  matter  in  the  soil 
must  be  continually  receiving  increase,  for  it  lives  almost 
entirely  on  animal  food — such  as  worms,  grubs,  insects, 
as  well  as  mice,  dead  birds,  hzards,  frogs — and  as  it  is 
extraordinarily  voracious,  large  numbers  of  these  must  be 
consumed,  their  remains,  digested  or  not,  being  left  in  the 
earth.  Large  quantities  of  vegetable  matter  are  also 
carried  into  its  nest  by  the  mole  every  year,  and  there 
they  are,  of  course,  left  to  decay.  When,  therefore,  one 
thinks  of  the  thousands  of  moles  still  existing,  and  the 
many  more  thousands  and  milhons  of  past  countless  gene- 
rations, every  one  of  which  lives,  or  lived,  the  same  sort  of 
life,  always  burrowing,  always  feeding,  and  always  making 
nests  year  by  year,  it  is  evident  that  their  effect  upon  the 
soil — in  places  where  they  are,  or  have  been,  plentiful — 
can  certainly  not  be  small. 

And  now  we  turn  to  another  very  different  set  of  work- 
ers, most  unlikely  ones  we  should  say  at  first  sight,  who 
are  helping  to  improve  and  prepare  some  of  the  limy 
mud-flats  of  the  East  Indian  Archipelago.  At  present, 
we  believe,  their  work  has  been  watched  only  on  the  Keel- 
ing or  Coroz  Islands;  but  what  crabs  are  doing  now  crabs 
may  have  done,  and  have  most  probably  done,  in  the  past, 
so  that  some  part  at  least  of  the  present  fertility  of  other 
mud-flats,  perhaps  of  coral  islands,  may  be  owing  to  them. 


52 


The  Great  World's  Farm 


But  what,  it  may  be  asked,  can  crabs  do?  They  bur- 
row, for  one  thing;  and  they  make  their  homes  so  close 
together,  that  as  many  as  a  hundred  and  twenty  of  these 
narrow,  corkscrew  holes  have  been  counted  in  a  space 
only  two  feet  square,  so  that  the  ground  is  very  thoroughly 
perforated  indeed.  And  they  not  only  burrow,  but  are 
incessantly  busy  carrying  down  twigs,  bits  of  seaweed, 
scraps  of  coconut  shell,  seeds,  and  so  forth,  with  the 
object  of  making  themselves  comfortable,  it  is  to  be  sup- 
posed, and  yet  it  almost  seems  as  if  they  labored,  some  of 
them,  in  this  industrious  way  simply  and  solely  for  the 
sake  of  improving  the  soil. 

One  of  these  crabs  works  so  near  the  water  that  its 
burrows  are  covered  at  high  tide;  another  works  a  little 
further  in,  and  a  third  further  still,  where  the  mud  is  dry; 
but  what  is  curious  about  this  last  is  that  as  soon  as  the 
white,  chalky  mud  has  been  turned  into  dark  vegetable 
soil,  which  it  is  by  the  decay  of  the  various  things  dragged 
into  it,  at  once  the  crab  goes  off  to  another  fresh  spot, 
and  begins  all  its  work  over  again.  Perhaps  it  does  not 
like  decayed  vegetable  matter;  but  the  result  is  that  it  is 
always  at  work,  and  must  get  through  a  good  deal  of 
digging  in  the  course  of  its  life. 

Beetles,  again,  are  most  useful  workers,  almost  all  the 
world  over,  and  on  some  of  the  wild  hill  slopes  of  Ireland 
all  the  patches  of  good  grass  are  said  to  be  their  work. 
Cows  are  kept  on  these  wastes,  and  are  attended  by  num- 
bers of  large  beetles.  Three  or  four  of  these  together  set 
to  work  at  a  patch  of  cow-dung,  burrowing  into  the  soil 
beneath,  and  bringing  up  little  heaps  of  clay  until  they 
have  covered  it  three  or  four  inches  deep.  Their  object, 
no  doubt,  is  to  make  a  suitable  place  in  which  to  lay  their 


Field-Laborers  53 

eggs,  for  the  grubs  when  hatched  Hve  upon  this  food;  but 
they  at  the  same  time  provide  a  suitable  bed  for  grass- 
seeds,  which  is  quickly  taken  possession  of. 

The  Dumble  Dor  beetle,  or  Flying  Watchman,  the 
slow,  hump-backed,  bluish  black  creature,  which  is  often 
found  lying  on  its  back,  goes  to  work  in  a  different  way, 
and  in  spite  of  its  slow  movements  gets  through  what  is 
really  an  amazing  amount  of  work  for  its  size.  We  all 
know  it  probably,  though  we  may  not  all  have  watched  its 
operations.  It,  too,  is  an  attendant  upon  cattle,  and 
works  so  expeditiously  and  in  such  large  numbers  as  to 
clean  a  meadow  tenanted  by  cows  in  three  or  four  days. 
Instead  of  bringing  up  earth  to  cover  the  droppings,  it 
removes  them  altogether,  pellet  by  pellet.  It  digs  its 
way  down  between  the  grass-roots,  carrying  with  it  as 
much  as  it  can  to  a  hole  a  foot  deep,  where  it  lays  one 
egg;  after  which  it  crawls  up  again  for  more,  over  and 
over  again,  making  many  journeys.  As  many  as  forty  or 
fifty  burrows  have  been  counted  in  one  square  foot. 

Burying  beetles,  of  one  species  or  other,  are  every- 
where plentiful,  so  plentiful  indeed  that  we  very  seldom 
meet  with  the  dead  bodies  of  bird,  mouse,  or  mole,  or  any 
other  animal,  in  our  walks  in  field  or  wood.  All  have 
been  cleared  away  and  buried  several  inches,  sometimes 
nearly  a  foot,  underground,  where  they  benefit  the  soil, 
besides  providing  food  for  the  beetle's  family — this  latter 
being  of  course  the  only  object  which  the  beetle  has  in 
view.  They  work  sometimes  singly,  sometimes  in  com- 
pany, scraping  the  earth  away  from  beneath  the  carcass 
with  their  forelegs,  and  then  carefully  covering  it  up; 
after  which  they  burrow  down  and  lay  their  eggs.  Four 
beetles  which  were  kept  and  watched  for  fifty  days,  buried 


54  The  Great  World's  Farm 

in  that  time  four  frogs,  three  small  birds,  two  fish,  one 
mole,  two  grasshoppers,  the  entrails  of  a  fish,  and  two 
pieces  of  ox-liver.  But  even  rabbits  are  not  too  large  for 
them;  and  one  foreign  species  will  bury  a  snake  in  a  few 
hours. 

QUESTIONS  FOR  REVIEW 

1.  What  is  necessary  for  soil  beside  mineral  substances? 

2.  How  has  the  soil  been  enriched  in  past  ages? 

3.  What  services  do  burrowing  animals  render? 

4.  Give  instances  of  the  diffusion  of  these  animals. 

5.  What  is  the  case  for  and  against  the  mole? 

6.  Show  how  the  crabs  improve  the  soil. 

7.  Describe  the  field  labors  of  various  kinds  of  beetles. 


CHAPTER  VII 

FIELD-LABORERS— Continued 

"The  plow  is  one  of  the  most  ancient  and  most  valu- 
able of  man's  inventions;  but  long  before  he  existed  the 
land  v^^as,  in  fact,  regularly  plov^ed,  and  still  continues  to 
be  thus  plowed,  by  earthworms." 

We  have  learned  much  about  the  earthworm  of  late 
years,  thanks  to  Mr.  Darwin;  but  long  before  Vegetable 
Mould  and  Earthworms  was  written — more  than  a  hun- 
dred years  ago,  in  fact — Gilbert  White,  the  naturalist,  of 
Selborne,  had  a  very  good  idea  of  the  worm's  importance 
as  one  of  nature's  field -laborers.  "A  good  monography 
of  worms,"  he  wrote,  "would  afford  much  entertainment 
and  information  at  the  same  time,  and  would  open  a  large 
and  new  field  in  natural  history."  "Vegetation  would 
proceed  but  lamely  without  it,  so  great  are  its  services  in 
boring,  perforating,  and  loosening  the  soil,  and  rendering 
it  pervious  to  rains  and  the  fibers  of  plants,  by  drawing- 
straws  and  stalks  of  leaves  and  twigs  into  it,  and  most  of 
all,  by  throwing  up  such  infinite  numbers  of  lumps  of  earth, 
which  is  a  fine  manure  for  grain  and  grass." 

Gardeners  and  farmers  hated  the  worm  in  his  day,  as 
the  former  at  least  do  still;  but  he  remarks  that  they 
would  find  "the  earth  without  worms  would  soon  become 
cold,  hard-bound,  and  void  of  fermentation,  and  conse- 
quently sterile." 

The  earthworm  is  an  animal   possessed  apparently  of 

55 


56  The  Great  World's  Farm 

more  than  the  traditional  nine  Hves,  and  endowed  with  a 
wonderful  power  of  adapting  itself  to  the  most  diverse  and 
most  adverse  circumstances.  Bodily  injury  affects  it  but 
little,  so  far  as  life  is  concerned.  One  worm  is  said  to 
have  been  beheaded  eight  times  in  succession,  and  to  have 
perseveringly  grown  a  new  head  each  time;  another  was 
cut  into  fourteen  pieces,  thirteen  of  which  became  perfect 
worms,  while  only  one  died. 

Earthworms  closely  similar  in  appearance  to  those 
which  we  know  in  England  are  found  in  soils  of  the  most 
various  kinds  and  in  almost  all  parts  of  the  world.  Moist- 
ure, however,  they  cannot  do  without,  and  hence,  while 
they  avoid  dry  sand  and  heaths,  they  frequent  paved  yards 
near  houses  in  large  numbers. 

On  the  mountains  of  North  Wales  and  on  the  Alps 
they  are  rare,  owing  perhaps  to  the  lack  of  sufficient  depth 
in  which  to  make  their  winter  burrows;  but  they  are  found 
in  Scotland  on  hills  fifteen  hundred  feet  above  the  sea; 
near  Turin,  at  a  height  of  two  thousand  or  three  thousand 
feet;  on  the  Nilgiri  Mountains  of  South  India,  and  on  the 
Himalayas.  They  have,  indeed,  an  enormous  range, 
occurring  in  the  most  isolated  islands,  abounding  in  Ice- 
land, and  found  in  the  West  Indies,  St.  Helena,  Mada- 
gascar, New  Caledonia,  Tahiti,  Kerguelen's  Land,  and 
the  Falkland  Islands,  though  how  they  reached  these  is  at 
present  a  mystery,  since  sea  water  is  absolutely  fatal  to 
them. 

Almost  the  whole  surface  of  every  moderately  damp 
country  is  covered  with  a  layer  of  fine,  dark,  vegetable 
mold;  it  is  only  a  few  inches  thick  at  most,  from  four 
or  five  to  perhaps  twelve  inches,  but  no  matter  what  the 
nature  of  the  soil  beneath,  there  it  is.     One  may  see  it  in 


Field-Laborers  ^j 

any  railway  cutting,  or  on  the  top  of  any  bank,  be  it  chalk 
or  be  it  sand;  and  this  black  earth,  or  humus,  is,  to  a 
very  large  extent,  the  work  of  worms. 

In  a  very  loose  soil  worms  can  move  easily,  but  gener- 
ally speaking,  as  their  bodies  are  soft,  and  cannot  pierce 
through  anything  at  all  hard  or  close,  and  as  they  have 
nothing  but  their  mouths  to  work  with,  they  are  obliged 
to  eat  their  way  through  the  ground.  No  doubt  they  are 
fed,  to  some  extent,  by  the  animal  or  vegetable  matter 
contained  in  the  soil,  but  their  primary  object  in  swallow- 
ing it  does  not  seem  to  be  food;  to  swallow  it  is  the  only 
way  they  have  of  getting  rid  of  it,  and  their  real  object  is 
to  make  a  tube  or  burrow  in  which  to  live. 

The  effect  produced  upon  the  soil  by  its  passage 
through  their  bodies  is  very  marked:  it  is  not  only  ren- 
dered extremely  fine,  but  its  color  is  gradually  altered, 
becoming  darker  and  darker,  until,  after  repeated  swal- 
lowing, it  is  turned  almost  black.  The  layer  of  dark 
mold  which  covers  our  fields  is  dark  just  because  it  is 
composed  of  the  castings  of  worms — castings  which  have 
passed  through  their  bodies  over  and  over  again,  times 
innumerable. 

The  worm  has  no  teeth,  and  its  mouth  is  a  mere  open- 
ing, but  it  has  the  power  of  flattening  its  head  and  extend- 
ing it  on  each  side  of  this  opening  so  as  to  form  two  lips, 
with  which  it  is  able  to  grasp  leaves  and  other  things  firmly 
enough  to  drag  them  into  its  burrow.  Sometimes,  how- 
ever, it  seems  to  vary  its  manner  of  proceeding,  and 
instead  of  grasping  the  object  it  wishes  to  move,  it  presses 
its  mouth  upon  it  until  it  adheres  firmly  by  mere  suction. 

Worms  are  omnivorous :  they  will  eat  anything  eatable, 
and  will  feed  daintily  upon  half-decayed  flowers  and  almost 


5  8  The  Great  World's  Farm 

any  kind  of  vegetable  matter,  or  coarsely  upon  their  own 
dead  comrades,  or  meat  when  put  in  their  way.  But  their 
chief  food  consists  of  half-decayed  leaves,  enormous  quan- 
tities of  which  are  pulled  into  their  burrows,  torn  into 
smaU  shreds,  and  then  swallowed  and  digested;  and  it  is 
this  vegetable  matter  which  changes  the  color  of  the  earth 
which  the  worms  swallow  with  it,  and  converts  it  into 
"mold" — vegetable  mold. 

Two  w^orms  kept  in  a  large  pot  of  sand,  well  moistened, 
of  course,  but  consisting  only  of  mineral  matter,  converted 
the  top  layer  into  vegetable  mold  four  inches  deep, 
simply  by  the  help  of  the  leaves  strewed  on  the  surface. 

Seeing  only  the  little  dark  heaps  of  soil  thrown  up  by 
worms  on  grass-plots  and  gravel-paths,  heaps  which  are 
soon  washed  down  again  by  rain,  one  has  some  difficulty 
in  realizing  the  vast  amount  brought  up  in  the  course  of 
a  year.  But  Mr.  Darwin  reckoned  that  near  Nice  this 
amounts  to  from  about  fourteen  to  eighteen  tons  to  the 
acre ;  this  is  supposing  them  to  be  as  numerous  and  active 
over  the  whole  of  the  field  as  they  were  in  the  one  square 
yard  chosen  for  observation;  but  it  is  also  supposing  them 
to  work  for  only  six  months  of  the  year,  which  he  con- 
sidered a  low  estimate.  The  largest  amount  was  brought 
up  on  very  poor  pasture,  where  leaves  were  probably 
scarce,  and  the  worms  had  to  swallow  much  earth  in 
order  to  obtain  sufficient  food. 

On  the  whole  it  seems  probable  that  they  bring  up 
more  than  ten  tons  of  soil  to  the  acre  in  many  parts  of 
England  year  by  year,  and  that  the  entire  mass  of  mold — 
the  dark  surface-soil  of  every  field — passes  through  their 
bodies  in  the  course  of  a  few  years,  and  is  by  these  means 
sifted  and  rendered  extremely  fine,   besides  being  thor- 


Field-Laborers  59 

oughly  impregnated  with  vegetable  and  animal  matter. 
Moreover,  bones,  twigs,  leaves,  shells,  are  constantly 
being  covered  with  castings,  and  these  further  help  to 
enrich  the  soil  by  their  decay;  whereas,  left  upon  the 
surface,  they  would  benefit  it  but  little. 

Besides  grinding  up  the  soil  in  the  process  of  digestion 
to  a  state  of  extreme  fineness,  besides  adding  to  it  vege- 
table matter  and  darkening  its  color,  worms  are  most  use- 
ful in  another  way:  they  prepare  channels  through  which 
the  roots  of  plants  are  able  to  spread  with  ease.  Plants 
evidently  prefer,  when  they  can,  to  take  advantage  of 
ready-made  passages,  and  worm  burrows  which  have  been 
in  existence  some  little  time  are  usually  found  lined,  to  the 
very  end  with  fine  roots  and  rootlets,  the  latter  covered 
with  fine  hairs,  through  all  of  which  the  plant  absorbs 
food.  But  that  the  worm's  way  of  top-dressing  lawns 
and  paths  does  not  improve  the  appearance  of  either,  we 
must  admit;  top-dressing  may  be  all  very  well  in  a 
meadow,  or  in  the  rice-fields  of  Bengal,  which  are  very 
soon  studded  with  worm-heaps  after  they  have  been 
flooded,  but  in  a  garden  we  are  inclined  to  think  it  out  of 
place.  And  it  is  true  that,  in  the  Botanic  Gardens  of 
Calcutta,  the  lawns  are  covered  in  a  single  night  or  two, 
if  they  are  left  unrolled,  with  tower-like  castings,  which 
weigh  some  ounce  and  a  quarter  each,  and  are  anything 
but  sightly. 

Sometimes,  too,  the  earthworm  may  disturb  seedhngs 
by  burrowing,  but  it  does  not  eat  them.  Neither  does  it 
touch  living  roots,  as  it  has  been  suspected  of  doing,  at 
least  when  these  are  growing  in  the  open  ground;  though 
what  it  may  do  when  confined  in  a  pot,  and  pressed  by 
hunger,  is  perhaps  another  matter. 


6o  The  Great  World's  Farm 

The  poor  worm  cannot  work  in  dry  soil.  Indeed, 
moisture  seems  to  be  the  one  thing  essential  to  it;  for 
though  it  can  stand  much  bodily  ill-usage,  it  is  actually 
killed  by  exposure  to  the  dry  air  of  a  room  for  even  a 
single  night.  In  hot  countries,  such  as  Bengal,  therefore, 
it  can  only  work  during  the  cool  season,  about  two 
months,  after  the  rains;  and  even  in  the  moist  climate  of 
England  it  cannot  work  near  the  surface  during  the  dry 
weather  of  summer,  any  more  than  in  hard  frost.  Gilbert 
White  remarked  that  worms  worked  most  in  spring;  but 
he  added  that  they  were  by  no  means  torpid  during  the 
dead  months,  and  were  in  fact  out,  even  in  winter,  on 
every  niild  night. 

There  is,  however,  another  and  much  smaller  animal, 
which,  as  some  people  think,  has  done  much  work  hitherto 
attributed  to  the  overpraised  worm.  Ants  have  not 
generally  had  the  reputation  of  being  useful  to  the  agri- 
culturist, however  clever  some  of  them  may  be  as  agricul- 
turists on  their  own  account;  but  in  Ireland,  according  to 
at  least  one  observer,  they  do  appear  to  have  been  most 
useful;   and  if  in  Ireland,  then  why  not  elsewhere.'' 

However,  whatever  their  respective  merits,  the  ants 
work  where  and  when  the  worms  cannot  do  so,  and  are 
most  useful  where  there  are  crags,  or  large  stones,  with 
patches  of  sandy  peat;  for  the  hill-building  ants  always 
choose  rock  to  build  upon,  and  gradually  cover  the  sur- 
face with  soil.  These  patches  are  at  once  taken  posses- 
sion of  by  grass  and  other  seeds,  and  so  the  soil  is  kept  in 
place.  During  the  winter  there  may  be  a  little  loss  by 
wind  and  rain,  but  the  greater  part  is  held  together  by 
the  roots,  and  a  patch  of  permanent  vegetation  is  formed 
where  previously  there  was  only  bare  stone. 


I 


Field- Laborers  6i 

A  single  colony  of  ants  seldom  covers  less  than  two 
square  feet,  and  sometimes  more  than  three;  and  as  they 
generally  choose  a  fresh  place  every  year,  they  really  do  a 
great  deal  towards  clothing  bare  places. 

In  the  sub-tropical  parts  of  South  America  and  India, 
worms  swarm  out  in  endless  numbers  when  the  rain  comes, 
but  in  the  tropics  proper,  except  in  the  moister  regions, 
they  are  on  the  whole  few.  Not  one  was  seen  by  Pro- 
fessor Drummond  in  Central  Africa,  even  during  rain, 
and  he  suggests  that  their  place  is  taken  in  these  parts 
by  the  termite,  commonly,  though  erroneously,  called 
the  white  ant. 

The  white  ant  lives  underground,  and  being  quite 
defenseless,  it  has  such  a  dread  of  exposure  that  when 
obliged  to  come  out  for  food  it  brings  some  of  the  earth 
with  it,  and  builds  a  tunnel  within  which  it  always 
remains. 

The  food  of  the  termite  is  dead  wood,  and  not  content 
with  what  it  finds  on  the  ground,  it  climbs  the  trees  in 
search  of  it,  toilsomely  carrying  earth  for  its  tunnels 
wherever  it  goes.  There  may  be  perhaps  a  few  feet  of 
dead  wood  at  the  end  of  a  long  branch  some  thirty  feet 
from  the  ground,  and  the  whole  distance  must  be  covered 
in  if  the  termite  is  to  reach  it.  But  as  it  does  not  know 
exactly  where  the  food  desired  is  to  be  found,  it  more 
often  than  not  covers  the  whole  tree  with  tunnels  and 
galleries  made  on  speculation. 

The  extent  to  which  this  tunneling  is  carried,  and  the 
amount  of  earth  brought  up,  are  something  incredible.  In 
some  districts  of  tropical  Africa  there  are  millions  of 
trees  covered  with  tubes,  every  one  of  which  must  be 
plastered  over  with  many  pounds  of  soil.     The  tunnels 


62  The  Great  World's  Farm 

generally  are  about  the  size  of  a  small  gas-pipe,  some 
occasionally  larger,  and  here  and  there  are  large  chambers 
covering  nearly  the  whole  trunk  for  some  feet.  Every 
branch,  every  twig  has  a  tunnel,  and  as  for  the  dead  wood 
which  falls  to  the  ground,  none  is  ever  to  be  seen,  as  it  is 
at  once  encased  in  soil.  At  first  sight  the  traveler  may 
think  he  has  found  a  faggot,  but  on  closer  inspection  it 
proves  to  be  nothing  but  a  cast  in  mud,  a  very  perfect 
cast,  with  all,  even  the  minutest  knots  reproduced.  But 
of  trunks,  branches,  boughs,  or  even  twigs  lying  about 
on  the  ground,  there  is  nothing  to  be  seen.  All  are 
eaten  up. 

But  the  tunnels  do  not  represent  nearly  all  the  termite's 
work,  though  they  are  much.  Besides  these,  there  are 
the  nests,  mounds  of  earth  of  huge  size,  which  are  a  com- 
mon feature  of  the  African  landscape,  and  can  be  seen 
for  miles.  In  India  they  are  seldom  more  than  a  couple 
of  feet  or  so  in  height,  but  in  Central  Africa  they  are 
from  ten  to  seventeen  feet  high  and  contain  many  tons  of 
earth,  while  the  excavations  beneath  are  many  feet  and 
even  yards  deep. 

The  mounds  are  not  solid,  but  composed  of  many  tun- 
nels, chambers,  and  galleries,  yet  they  are  so  strong  that 
they  will  bear  the  weight  of  a  man  on  horseback.  The 
exterior  is,  indeed,  brick-like  or  stone-like  in  its  hardness, 
but  with  all  its  strength  it  must  give  way  at  last  beneath 
the  fury  of  the  tropical  rains,  which  continue  off  and  on 
for  two  or  three  months  at  a  time,  and  thus  the  soil  is 
returned  to  the  earth  enriched  by  its  admixture  with  ani- 
mal matter. 

Ants,  true  ants,  as  well  as  white  ants,  abound  every- 
where within  the  tropics,  but  they  also  do  a  large  amount 


Field-Laborers  6^ 

of  work  outside,  though  their  numbers  gradually  diminish 
as  we  go  further  and  further  north  and  south. 

There  are  **ant  cities"  in  Pennsylvania,  each  of  which 
contains  more  than  sixteen  hundred  nests  of  various  size, 
the  largest  being  fifty-eight  feet  round  the  base  and  forty- 
two  inches  high,  with  galleries  some  sixty  feet  long  lead- 
ing to  the  feeding  grounds. 

The  muscular  power  of  these  ants  is  truly  wonderful. 
The  loads  they  carry  are  twenty-five  times  their  own 
weight,  and  they  carry  them  what,  for  their  size,  is  an 
enormous  distance.  It  is  as  if  a  man  of  ordinary  size 
were  to  carry  a  weight  of  four  thousand  pounds  from  the 
bottom  of  a  coalpit  to  the  top  of  the  Great  Pyramid. 
And  they  have  not  merely  to  carry  these  loads,  but  first 
to  prepare  them. 

The  ant  begins  work  by  scratching  with  her  forelegs 
like  a  dog;  later  on  she  bites,  cuts,  or  twists  off  pellets  of 
earth,  during  which  process  she  often  works  like  a  coUier 
on  her  back,  and  then  she  compresses  the  particles  into  a 
ball  and  carries  them  out.  The  only  implements  she  has 
for  her  work  are  her  mandibles,  or  first  pair  of  jaws, 
which  are  placed  outside  her  mouth,  each  jaw  being  fur- 
nished with  seven  teeth.  These  powerful  jaws  serve  as 
pick,  shovel,  crowbar,  saw,  axe,  and  cart,  all  in  one,  and 
as  the  little  creature  grows  old  her  teeth  are  gradually 
worn  down  by  the  hard  work  they  have  done,  just  as  a 
workman's  tools  are  worn. 

Thus  not  only  is  fresh  soil  continually  exposed  to  the 
action  of  air  and  rain,  but  ways  are  opened  by  which  the 
same  air  and  rain  may  penetrate  to  the  underlying  rocks 
and  carry  on  the  decaying  process,  as  described  in  an 
earlier  chapter.     Nor  must  it  be  forgotten  that  wherever 


64  The  Great  World's  Farm 

there  is  decaying  vegetable  matter,  there  carbon  dioxide 
and  other  gases  are  formed,  which  are  absorbed  by  the 
rain  in  its  passage  through  the  earth,  and  increase  in  a 
very  high  degree  its  power  of  acting  upon  the  rocks 
beneath. 

We  cannot  attempt  to  give  more  than  a  sketch,  and 
that  a  very  shght  one,  of  the  work  done  by  nature's  vari- 
ous field-laborers;  but  slight  as  it  is,  it  would  be  incom- 
plete without  some  mention  of  the  very  curious  animals 
known  as  ant-eaters,  which  are  found  throughout  the 
tropics. 

These  creatures  have  very  long,  thin,  pliable  tongues, 
looking  like  red  earthworms,  and  as  if  they  were  endowed 
with  independent  life;  and  when  they  can  get  at  them 
they  lick  up  the  ants  with  marvellous  rapidity. 

The  ants,  as  we  have  seen,  dwell,  many  of  them,  within 
walls  almost  as  hard  and  strong  as  if  built  of  stone  or 
brick,  capable,  one  would  think,  of  defying  the  attack  of 
almost  any  animal.  But  ant-eaters  are  armed  with  tre- 
mendously powerful  claws — so  powerful  that  with  them 
they  are  able  to  dig  and  tear  down  even  these  strong  cita- 
dels; and  this  done,  they  sweep  up  the  terrified  inhabi- 
tants by  thousands. 

The  great  ant-eater,  or  ant-bear  of  tropical  South 
America,  is  like  the  Aard-Vark,  but  larger,  and  is  so  bold 
that  it  will  sit  up  and  fight  even  a  "tiger,"  or  more  prop- 
erly jaguar,  with  the  very  long,  curved  claws  of  its  fore- 
feet. Yet  notwithstanding  its  size  and  strength,  it  lives 
chiefly  on  ants. 

By  this  and  other  ant-eaters  the  hills  and  mounds  of 
the  ants  are  demolished,  and  the  earth  which  they  have 
excavated  with  so   much  labor  is  returned  to  the  soil. 


Field-Laborers  65 

And  it  is  returned  in  an  altered  state,  much  finer  than 
before,  and  enriched,  to  some  extent  at  least,  by  what  has 
been  added  to  it,  and  so  is  better  fitted  for  the  support  of 
plant-life. 

QUESTIONS  FOR  REVIEW 

1.  Describe  the  habits  of  the  earthworm. 

2.  How  is  the  soil  enriched  by  them? 

3.  In  what  parts  of  the  world  are  they  found? 

4.  How  do  ants  accomplish  what  worms  cannot? 

5.  Describe  the  habits  of  the  termite. 

6.  What  remarkable  "ant  cities"  are  found  in  Pennsylvania? 

7.  How  are  these  ants  equipped  for  their  work? 

8.  What  does  the  soil  gain  from  their  efforts? 

9.  What   part  does  the  ant-eater  play  as  one  of  nature's 
laborers? 


CHAPTER  VIII 
WATER 

The  soil  may  have  been  ground  and  mixed,  perhaps 
transported  long  distances,  and  otherwise  prepared  by  the 
various  laborers  already  described;  but  even  then  no 
crops,  whether  wild  or  cultivated,  can  thrive  in  it  without 
moisture.  In  perfectly  dry  soil  they  must  starve  in  the 
midst  of  plenty;  for  they  can  no  more  get  at  the  food 
around  them,  however  abundant  it  may  be,  without  water, 
than  if  it  were  locked  up.  To  them,  indeed,  under  such 
circumstances,  it  is  locked  up. 

Of  course,  we  all  know,  as  a  matter  of  fact,  that  plants 
fade  and  wither,  and  eventually  shrivel  and  die,  if  they  be 
kept  without  water.  We  may  know,  too,  that  three- 
quarters  of  the  weight  of  most  plants,  and  a  great  deal 
more  of  many,  is  made  up  of  nothing  but  water.  But 
when  once  they  have  had  a  supply  of  water,  why  should 
they  need  more?  Cannot  they  keep  it?  and  if  not, 
how  do  they  lose  it?  Why  do  they  need  constant  water- 
ing? 

A  potato  is  watery:  only  one-fourth  of  its  weight  is 
solid  matter;  the  rest  is  all  water.  An  artichoke  con- 
tains still  more  water,  and  still  less  solid  matter;  a  turnip 
is  more  watery  still;  and  a  pumpkin  contains  only  five 
and  a  half  per  cent  of  solid  matter. 

And  yet,  when  we  have  stored  our  potatoes  and  tur- 
nips, or  our  pumpkins,  we  do  not  find  it  necessary  to 

66 


Water  67 

water  them.  They  do  not  shrivel;  they  keep  their  moist- 
ure.    Why  does  not  a  plant  do  the  same.-* 

The  only  answer  to  this  question  is,  simply  because  it 
can't.  It  cannot  shut  the  many  mouths  by  which  it  is 
constantly  losing  moisture.  We  human  beings  cannot 
prevent  the  escape  of  water  through  the  pores  of  our  skin, 
or  in  the  breath  which  we  breathe;  and  the  plant  is  in 
similar  case.  It  is  constantly  giving  off  water,  and  if  the 
loss  is  not  made  up  it  must  needs  become  dry  and  shrivel. 

Almost  every  part  of  a  plant  which  is  exposed  to  the 
air,  and  not  covered  by  a  layer  of  cork  or  of  thickened 
skin,  is  constantly  losing  moisture  in  ordinary  air;  and 
unless  the  roots  can  suck  up  enough  to  make  the  loss 
good,  it  droops,  flags,  withers,  and  dies. 

The  potato  and  the  pumpkin  are  protected — the  one 
by  cork,  the  other  by  thick  skin — and  they  are  therefore 
able  to  retain  their  moisture  for  a  considerable  time.  In 
a  similar  way,  the  stems  of  most  woody  plants  and  trees 
are  protected  by  layers  of  cork,  and  often  of  fibrous  bark 
as  well,  which  almost,  though  not  altogether,  prevent  the 
escape  of  water.  It  is  the  young,  green  stems,  the  grow- 
ing parts,  and  the  leaves  by  which  it  is  chiefly  aUowed  to 
go  off  into  the  air;  and  these  are  just  the  parts  which 
especially  need  the  mineral  food,  the  food  derived  from 
the  soil,  which  the  roots  are  constantly  preparing. 

How  are  the  roots  to  convey  this  food  to  the  growing 
parts  of  the  plant?  Of  course,  they  cannot  do  so;  they 
can  only  make  it  ready,  and  then  it  must  be  pumped  up 
to  where  it  is  wanted.  Accordingly,  as  the  water  is  drawn 
off,  so  to  say,  above,  the  sap  from  below — that  is,  water 
containing  food  from  the  soil— rises  to  supply  its  place. 

A   constant   current,   therefore,    rises   from   the   roots 


68  The  Great  World's  Farm 

upwards;  but  a  great  deal  of  this  would  be  lost  during  its 
passage  before  it  reached  the  young  shoots  but  for  the 
fact,  already  mentioned,  that  the  trunks  or  stems  through 
which  it  passes  are  protected  against  the  air,  and  moisture 
can  escape  but  very  slowly  through  bark  or  cork,  though 
it  does  still  escape  to  some  small  extent. 

When  the  sap  reaches  the  green  parts  of  the  plant  it 
passes  off  into  the  air  as  invisible  vapor;  or,  rather,  the 
water  of  the  sap  passes  off  in  this  way,  and  the  food  from 
the  soil,  the  mineral  matter,  is  left  behind.  But  even 
from  the  green  stems  and  leaves  the  water  is  not  allowed 
to  escape  quite  unchecked,  else  it  might  pass  off  too  fast — 
faster  than  it  could  be  supplied. 

For  anything  moist,  whether  it  be  moist  earth  or  wet 
clothes,  dries  when  exposed  to  the  air.  The  air  sucks  the 
moisture  out  of  all,  and  the  drier  the  air,  the  more  quickly 
it  sucks.  Without  some  protection  against  this  thirsty 
air,  therefore,  leaves  and  green  stems  would  also  be 
sucked  dry,  like  anything  else,  and  accordingly  their  outer 
skin  is  more  or  less  thickened;  and  it  often  contains,  or 
is  covered  by,  a  waxy  deposit  as  well.  We  may  perhaps 
have  noticed  how  drops  of  dew  he  upon  the  leaves  without 
soaking  in,  so  that  when  the  dew  is  shaken  off,  the  leaves 
are  dry.  This  is  especially  noticeable  on  some  shiny 
leaves,  but  also  on  some  mealy-looking  ones,  as,  for 
instance,  cabbage  leaves;  and  in  both  cases  it  is  the  waxy 
substance  in  or  upon  the  skin  of  the  leaf,  which  not  only 
prevents  water  from  soaking  in,  but  also  prevents  all  but 
a  very  small  quantity  of  the  moisture  from  being  drawn  out. 

Then,  if  water  is  constantly  passing  off,  and  that  in 
considerable  quantities,  how  does  it  escape.?  A  Httle,  as 
we  have  said,  passes  off  through  the  whole  surface,  but 


Water  69 

the  bulk  finds  its  way  out  through  special  openings,  pores, 
or  mouths,  to  which  the  name  of  **stomata"  has  been 
given.  These  pores  are  extremely  minute  openings  in  the 
outer  skin  of  leaf  and  stem,  and  vary  very  greatly  in  size 
and  number  in  different  plants.  It  is  through  them  that 
used-up  air  and  water  in  the  form  of  vapor  are  allowed  to 
escape. 

The  process  by  which  vapor  is  given  off  through  the 
leaf-pores  is  called  ''transpiration,"  and  is  not  the  same 
thing  as  evaporation,  though  like  it,  it  proceeds  more 
quickly  in  hot,  dry  weather.  But  evaporation  goes  on — 
or,  in  other  words,  the  air  sucks  moisture — from  the  whole 
surface  of  a  plant — from  trunk,  stem,  and  leaves  more  or 
less,  and  would  suck  much  more  than  it  does  if  it  were 
not  prevented. 

Transpiration,  on  the  other  hand,  is  confined  to  the 
leaf-pores,  and  is  the  process  by  which  the  plant  parts  by 
its  own  action,  so  to  say,  with  its  superfluous  moisture. 
In  evaporation  the  plant  is  merely  acted  upon  by  the  air; 
the  moisture  is  sucked  out  as  it  is  sucked  from  a  wet 
sheet  hung  out  to  dry,  or  a  piece  of  dead  wood.  In 
transpiration  the  moisture  passes  out  through  the  proper 
openings,  and  the  plant  itself  acts,  or  at  least  discharges 
one  of  the  natural  functions  of  its  being.  Evapora- 
tion may  continue  in  a  dead  plant,  but  only  a  living  plant 
transpires. 

Both  processes  are  affected  by  the  weather,  however, 
and  both  in  a  similar  way. 

Nothing,  we  know,  dries  on  a  very  damp  day,  because 
the  more  moisture  the  air  contains,  the  less  it  can  take 
up;  or,  in  other  words,  evaporation  proceeds  slowly  in 
moist  air.     So,  too,  transpiration  almost  or  quite  ceases 


70  The  Great  World's  Farm 

in  damp  weather,  or  when  the  leaves  are  wet.  But  both 
go  on  more  briskly  in  the  sun,  in  dry  air,  and  more  espe- 
cially in  a  drying  wind. 

The  leaf-pores  by  which  transpiration  proceeds  are 
usually  more  abundant  on  the  under  surface — the  shady 
side — of  the  leaves,  and  are  few  or  altogether  wanting  on 
the  upper  surface,  where  they  would  be  exposed  to  the 
sun,  and  water  might  pass  off  too  rapidly.  In  moist, 
shady  situations  there  is  no  danger  of  too  much  trans- 
piration, and  plants  growing  in  these  not  only  have  more 
leaf-pores  than  others,  but  can  also  have  them  without 
risk,  both  on  the  under  and  upper  surface  of  the  leaves, 
for  here  transpiration  goes  on  more  slowly,  and  the  loss 
of  water  is  also  easily  made  up. 

Thick,  fleshy  leaves  have  the  fewest  leaf-pores,  and 
thick,  fleshy  leaves  are  particularly  characteristic  of  hot 
countries,  where  plants  can  afford  to  lose  but  little  of  the 
scanty  supply  of  water  which  comes  to  them. 

Many  leaves  which  are  alike  on  both  sides  have  about 
an  equal  number  of  pores  above  and  below;  but  when 
there  is  any  difference,  as,  for  instance,  where  one  side  is 
dull  and  the  other  glossy,  the  dull  side,  which  is  also  the 
under  side,  has  the  larger  number  of  pores.  The  leaves 
of  the  laurustinus  have  no  leaf-pores  at  all  on  their  shiny, 
upper  surface,  neither  have  those  of  the  lilac ;  while  those 
of  the  carnation,  which  show  no  such  difference  as  these 
do,  have  about  an  equal  number  on  each  side.  Some 
leaves  have  as  many  as  one  hundred  and  seventy  thousand 
pores  to  the  square  inch,  but  this  seems  to  be  the  largest 
number.  An  apple-leaf  of  ordinary  size  has  about  one 
hundred  thousand  leaf-pores  altogether. 

The  size  of  the  pores  varies  very  much,  but  at  their 


Water  y  i 

largest  they  are  so  minute  as  entirely  to  exclude  the  very 
finest  dust.  Those  of  the  white  Uly,  for  instance,  which 
are  called  * 'remarkably  large,"  measure  only  one  four 
thousand  two  hundred  and  fiftieth  part  of  an  inch  across. 

Hard,  evergreen  leaves,  such  as  those  of  the  pine,  are 
like  the  thick,  fleshy  ones  in  this,  that  they  have  but  few 
leaf-pores,  and  lose  but  little  water  except  through  these 
openings.  For  pines  grow  in  very  dry,  sandy  soils,  and 
often  in  elevated  situations,  where  the  air,  though  cold,  is 
exceedingly  dry  and  drying,  and  they  therefore  need 
as  much  protection  as  plants  which  grow  in  hot,  dry 
climates. 

Many  and  various  are  the  devices  by  which  evapora- 
tion is  checked  and  controlled,  even  in  temperate  latitudes, 
lest  the  plant's  need  of  water  should  exceed  the  supply. 
For  it  must  be  remembered  that  air  has  an  immense  appe- 
tite for  water;  the  drier  it  is  the  more  it  takes  up,  but 
it  goes  on  sucking,  if  allowed,  as  long  as  it  is  in  contact 
with  anything  containing  moisture  until  it  can  hold  no 
more. 

It  is  this  which  makes  the  miseiy  of  an  east  wind, 
which  is  a  very  dry  wind,  as  well  as  a  cold  one,  and  sucks 
up  moisture  wherever  it  can,  not  only  from  vegetation, 
but  from  the  bodies  of  animals,  drying  the  skins  of  human 
beings  as  the  hot,  dry  air  of  the  desert  dries  them,  though 
in  less  degree. 

Since  three-fourths  of  the  weight  of  most  plants,  and 
more  of  many,  is  made  up  of  water,  the  air  would  be 
always  sucking  at  them,  if  not  prevented.  As  things  are, 
however,  though  some,  generally  very  small,  amount  of 
water  is  sucked  by  the  air  from  the  whole  surface  of  a 
plant,  as  we  have  said,  its  escape  is  confined,  as  far  as 


y2  The  Great  World's  Farm 

may  be,  in  most  cases,  and  especially  in  dry  climates,  to 
the  legitimate  openings,  the  pores  made  for  this  purpose. 

Soft,  thin  leaves  lose  water  by  evaporation  from  the 
whole  surface,  and  have  a  large  number  of  pores  as  well, 
but  they  grow  in  situations  where  they  can  easily  make  up 
the  loss.  All  leaves,  however,  have  some  protection 
more  or  less  in  the  skin  which  covers  them,  this  skin 
being,  moreover,  as  we  have  said,  impregnated  with  wax, 
which,  though  commonly  invisible,  often  appears  as  a 
shiny  coating,  or  as  "bloom." 

A  cabbage,  for  instance,  has  a  mealy  look  about  it,  as 
if  it  had  been  dusted  with  flour;  many  grasses,  acacias, 
and  now  well-known  Austrahan  gum-tree  or  eucalyptus, 
have  a  similar  appearance,  and  when  this  "bloom"  is 
examined  it  is  found  to  consist  of  minute  rods,  or  needles, 
of  wax.  The  substance  forms  a  regular  incrustation  on 
the  stem  of  the  Peruvian  wax-palm,  whose  native  land  is 
one  of  the  most  rainless  regions  of  the  earth;  and  there  is 
nothing  more  effectual  than  wax  for  excluding  air  and 
preventing  evaporation.  Honey  stored  in  wax-cells  is,  as 
it  were,  hermetically  sealed  up  and  preserved. 

With  the  wax  is  often  associated  resin,  which  acts  in  a 
similarly  protecting  way  apparently.  No  explanation 
indeed  has  hitherto  been  given  of  the  use  to  the  plant  of 
gums,  resins,  caoutchouc,  and  the  strong-smelling  oils 
frequently  found  in  leaves ;  but  as  water  in  which  gum  or 
any  other  substance  is  dissolved  evaporates  more  slowly 
than  pure  water,  it  seems  not  unlikely  that  one  at  least  of 
the  uses  of  these  substances  is  to  check  the  escape  of 
water.  And  this  seems  the  more  probable  when  we  con- 
sider that  aromatic  as  well  as  gum  and  resin-bearing 
plants   are    especially   characteristic   of    deserts   and   dry 


Water  yj 

regions,  hot  or  cold.  Thus  the  pine-tree  of  the  north  has 
its  turpentine,  the  eucalyptus  of  hot,  dry  Australia  its  oil, 
and  the  acacias  of  Africa  their  gums. 

Many  trees  and  shrubs  in  hot,  dry  countries  are  pro- 
tected also  by  having  either  small  or  very  few  leaves,  or 
even  none  at  all. 

Where  the  air  is  constantly  damp,  as  it  is  in  many 
parts  of  the  tropics,  there  the  trees  may  boldly  venture, 
as  the  plantain  does,  to  spread  broad  leaves  many  feet 
square  to  the  sun,  for  the  water-supply  never  fails,  and 
the  air  is  not  outrageously  thirsty,  as  it  is  in  the  desert. 
But  in  those  parts  of  Australia  where  rain  is  scanty  and 
droughts  are  frequent,  there  the  leaves  are  not  only  small, 
as  we  have  said,  but  they,  most  of  them,  also  protect 
themselves  by  turning  only  their  edges,  not  their  broad 
sides,  to  the  sun;  for  they  have  to  economize  their  re- 
sources as  much  as  possible.  This  is  particularly  the 
case  with  many  species  of  eucalyptus,  some  of  which  turn 
one  leaf-edge  to  the  earth  and  the  other  to  the  sky,  or 
stand  eiect,  turning  one  edge  towards  the  stem  and  the 
other  away  from  it,  in  each  case  exposing  themselves  as 
little  as  possible.  Their  leaves,  too,  are  for  the  most  part 
narrow,  and  so  scantily  distributed  over  the  branches  that 
an  Australian  forest  has  none  of  the  deep  shade  which  the 
word  naturally  suggests  to  us. 

But  when  the  eucalyptus  is  transported  to  other  lands. 
Where  it  has  plenty  of  deep,  rich  soil,  and  moisture  in 
abundance,  then  it  puts  on  more  foliage,  showing  that  it 
was  only  the  dry  heat  of  its  native  climate  which  made  it 
so  sparing  of  its  leaves. 

Most  of  the  many  species  of  acacia  found  in  Australia 
go  even  a  step  beyond  the  eucalyptus  in  the  way  of  econo- 


74  The  Great  World*s  Farm 

mizing  their  foliage,  and  give  up  having  any  true  leaves 
at  all  as  soon  as  they  are  full-grown.  They  keep  their 
leaf-stalks  indeed,  but  there  are  no  leaves  at  the  end  of 
them,  and  instead  there  are  ** wings,"  or  narrow,  leaf-like 
margins,  growing  out  from  each  side  of  the  stalks.  Even 
these  "wings"  do  not  venture  to  face  the  sun,  but  turn 
their  edges  to  earth  and  sky. 

Acacias  are  especially  the  trees  of  deserts;  they  are, 
indeed,  the  only  timber-trees  of  the  Arabian  Desert,  and 
they  abound  in  Africa,  as  also  in  Australia.  But  wherever 
they  grow  they  are  characterized  by  the  lightness  of  their 
foliage;  and  of  the  Australian  species,  which  number 
something  under  three  hundred,  two  hundred  and  seventy 
drop  their  leaves  altogether  when  they  are  grown  up,  and 
merely  flatten  out  their  leaf-stalks  as  described. 

None  of  the  cactus  family — which  are  natives  of  the 
hot,  dry  regions  of  America,  North,  South,  and  Central — 
make  any  attempt  at  having  leaves  or  even  "wings,"  but 
their  stems  are  flattened  out  and  do  duty  instead.  The 
stems,  too,  are  protected  against  evaporation  by  being 
enveloped  in  a  peculiar  leathery  skin,  which  is  thickest  in  the 
species  inhabiting  the  hottest  and  driest  regions;  and  they 
lose  little  water  therefore,  except  through  the  pores,  which 
are  but  few  in  number.  Thus  protected,  they  not  only 
exist,  but  flourish,  in  dry  sand,  where  for  three-quarters 
of  the  year  they  are  exposed  to  the  blazing,  parching  sun. 

The  tall,  fluted  columns  of  the  species  of  cactus  called 
the  "torch  thistle,"  sometimes  fifty  feet  high,  are  to  be 
seen  springing  out  of  crevices  in  the  hard  rock,  and  stand- 
ing up  like  telegraph-posts  on  the  mountains  and  in  the 
rocky  valleys  all  over  the  hot,  parched,  almost  desert 
regions  of  New  Mexico. 


Water  y^ 

This  tall  cactus  seems  to  be  so  fully  protected  by  its 
thick  skin  that  it  may  venture  to  expose  its  whole  surface 
to  the  sun  without  risk;  but  other  species  are  less  bold, 
and  keep  close  to  the  ground,  growing  in  the  form  of 
large  cushions,  or  great  globular  masses,  and  so  diminish- 
ing the  extent  of  exposed  surface.  Some,  too,  are  set  all 
over  with  long,  slender,  needle-like  spines,  and  are  also 
covered  with  what  look  like  dense  masses  of  floss  silk, 
both  of  which  protect  the  plant  from  the  hot  air  and  sun. 

But  though  these  special  means  of  defense  are  more 
striking  in  the  tropics  than  elsewhere,  they  are  employed 
more  or  less  everywhere,  our  own  moist  land  not  excepted. 
Besides  the  bark,  and  the  cork,  and  the  more  or  less  thick 
skin  of  the  leaves,  and  the  wax,  which  we  have  already 
mentioned  as  the  ordinary  means  by  which  evaporation  is 
checked,  these  other  measures  are  also  frequently  adopted 
for  securing  the  same  end.  Our  plants  do  not  indeed  go 
so  far  as  to  drop  their  leaves  altogether,  but  some  of  them 
do  greatly  diminish  both  their  number  and  size;  and  some 
clothe  themselves  with  hairs,  partly,  as  it  would  seem,  lest 
they  should  be  deprived  of  too  much  moisture,  though 
partly  also,  probably,  as  a  protection  against  insects.  An 
example  or  Iwo  of  these-  must  suffice,  and  we  will  take, 
first,  that  of  the  amphibious  persicaria — a  particularly 
interesting  plant,  as  it  grows  both  on  land  and  in  water, 
and  adapts  itself  to  its  situation  in  a  very  marked  manner. 
When  it  grows  in  water,  where,  of  course,  it  does  not 
matter  how  much  it  may  lose,  it  has  smooth,  lance-shaped 
leaves ;  but  when  it  grows  on  land  the  leaves  are  narrower, 
and  not  only  this,  but  they  are  covered  as  well  with  a 
quantity  of  long  hairs,  pressed  close  upon  the  surface, 
which  they  protect  against  evaporation. 


76  The  Great  World's  Farm 

Then  there  is  the  sweet  woodruff,  whose  lance-shaped 
leaves  grow  in  whorls  of  eight,  for  the  plant  dwells  in 
moist,  shady  places,  where  there  is  no  risk  in  having  many 
leaves.  But  look  from  this  to  another  member  of  the 
family,  the  quinsywort,  and  what  do  we  find?  The 
leaves  are  very  narrow,  and  there  are  but  half  as  many  of 
them.  Why?  Because  this  little  plant  grows  on  dry 
banks,  where  many  and  large  leaves  would  be  dangerous 
to  its  welfare. 

It  has  been  already  mentioned  that  the  pine  family, 
which  thrive  in  dry,  sandy  soils,  have  hard,  needle-like 
leaves,  with  few  pores,  and  therefore  give  off  but  little 
water,  either  by  evaporation  or  transpiration;  and  it  is  for 
this  reason  that  the  air  in  a  pine  forest  in  summer  has 
none  of  the  coolness  which  one  finds  in  a  forest  of  what 
the  Germans  call  * 'leaf-trees."  The  needles  of  the  pine 
they  do  not  consider  worthy  the  name  of  leaves. 

Leaf-trees  are  continually  cooling  the  air  by  the  moist- 
ure which  they  give  up  to  it;  but  the  pine-needles  have 
so  few  pores,  and  are  so  very  much  protected,  that  the 
little  water  they  part  with  is  not  enough  to  produce  any 
appreciable  effect  upon  the  air. 

It  is,  perhaps,  hardly  necessary  to  do  more  than 
remind  our  readers  that  the  evaporation  of  water  is  always 
accompanied  by  the  absorption  of  heat;  or,  in  other 
words,  that  water  cannot  be  converted  into  gas  or  vapor, 
which  it  is  when  evaporated,  without  using  up  heat. 
Whether  it  be  the  heat  of  a  fire  or  the  heat  of  the  sun,  it 
is  all  the  same.  A  certain  amount  of  heat  is  required  to 
make  water  pass  from  the  liquid  to  the  gaseous  state,  and 
if  this  heat  be  taken  from  the  air,  the  air  is  necessarily  by 
so  much  the  cooler. 


Water  y'7 

And  this  brings  us  to  another  part  of  the  subject,  the 
question,  namely,  as  to  the  amount  of  water  given  off  by 
trees  and  other  plants,  notwithstanding  the  various  ways 
in  which,  as  we  have  seen,  they  are  protected. 

We  have  distinguished  hitherto  between  the  two  pro- 
cesses of  evaporation  and  transpiration,  because  they  are 
distinct ;  the  one  being  due  to  the  action  of  the  air,  and 
the  other  to  the  action,  so  to  say,  of  the  plant.  Evapo- 
ration takes  place  whenever  air  comes  in  contact  with 
anything  moister  than  itself;  whether  it  be  animal  or 
vegetable,  whether  it  be  wet  earth  or  damp  clothes,  from 
all  it  draws  water,  and  by  its  own  heat  converts  this  water 
into  vapor.  The  other  process,  transpiration,  is  that  by 
which,  through  the  pores — the  openings  left  in  the  skin  of 
stem  and  leaf — the  plant  gives  up,  in  a  regular,  systematic 
manner,  the  moisture  with  which  it  would  else  be  over- 
charged. 

But  in  both  cases  the  water  passes  off  into  the  air  in 
the  form  of  vapor;  and  in  both  cases  it  passes  off  as 
nearly  pure  water,  all  mineral  matter  being  left  behind;  in 
both  cases  also,  the  amount  given  off  varies  with  the 
weather,  there  being  more  loss  on  a  hot,  dry,  sunny,  or 
windy  day,  than  on  a  damp,  dull,  still  one.  When,  there- 
fore, we  consider  the  amount  of  water  which  passes  off 
into  the  air  from  a  plant  in  a  certain  time,  it  is  generally 
impossible  to  distinguish  between  that  which  comes 
through  the  whole  surface  and  that  which  comes  through 
the  pores;  and  both  processes  are  frequently  spoken  of 
together  as  transpiration  or  evaporation.  The  quantity 
transpired  is,  however,  usually  very  much  larger  than  the 
quantity  evaporated. 

In  some  plants  it  is  occasionally  possible  to  see  the 


78  The  Great  World's  Farm 

moisture  coming  from  the  leaf-pores,  as  it  escapes  faster 
than  the  air  can  evaporate  it.  This  is  the  case  with  many- 
grasses,  especially  the  maize,  which  may  be  seen  studded 
with  actual  drops  of  water. 

A  grass-plant  gives  up  its  own  weight  of  water  in  the 
course  of  twenty-four  hours,  in  hot,  dry  weather;  and  a 
square  foot  of  turf  will  yield  more  than  one  and  one-fifth 
pints  of  water  in  this  time.  But  a  square  foot  of  long 
pasture-grass  gives  off  nearly  four  and  two-fifth  pints,  or 
as  much  as  one  hundred  and  six  tons  of  water  to  the  acre! 

The  larger  the  surface,  the  larger,  of  course,  the  amount 
of  water  which  passes  off  from  it;  and  therefore  the  extent 
of  surface  exposed  is  a  matter  of  great  importance,  though 
it  is  also  one  which  we  are  very  likely  to  overlook,  at 
least  in  many  cases.  Of  course  we  can  all  see  that  a 
tropical  plantain,  with  its  broad,  large  leaves,  has  a  con- 
siderable surface  exposed  to  sun  and  air;  and  so  with 
other  conspicuously  large-leaved  plants.  But  when, 
instead  of  a  few  large  leaves,  a  plant  has  many  small 
ones,  it  is  not  so  easy  to  realize  what  the  whole  surface 
may  amount  to. 

A  sunflower,  for  instance,  has  leaves  of  a  good  size, 
and  yet  it  is  rather  surprising  to  find  that  in  a  plant  only 
three  feet  and  a  half  high,  the  whole  leaf-surface  may 
amount  to  more  than  thirty-two  square  feet!  One  speci- 
men of  this  size  was  found  to  give  up  from  a  pint  to  a  pint 
and  a  half  of  water  during  a  day  of  twelve  hours.  The 
sunflower  is  quite  outdone  by  the  cabbage,  however,  one 
specimen  of  which  gave  off  nearly  two  pints  and  a  half  in 
twenty-four  hours,  and  that  from  leaves  which,  had  they 
been  spread  out,  would  have  covered  only  nineteen  square 
feet.     We  have  seen  how  well  the  cabbage  is  protected  by 


Water 


79 


its  wax  coating  against  evaporation,  so  that  almost  the 
whole  of  this  amount  is  given  off  by  the  plant's  own  action. 
The  camellia  is  much  less  thirsty;  it  has  fewer  pores,  and 
its  thick,  glossy  leaves  are  so  efficiently  protected,  that 
half  an  ounce  of  water,  one-fortieth  pint  to  the  square 
foot  of  foliage,  was  all  that  one  plant  gave  up  in  a  day 
and  night. 

These  calculations  are  comparatively  simple;  but 
when  we  come  to  trees,  who  would  venture  to  guess  at  the 
extent  of  surface  exposed  to  the  air  and  sun  by  the  leaves 
upon  an  elm?  We  look  up  at  the  quivering  multitudes, 
and  feel  as  if  it  were  hopeless  for  any  one  even  to  attempt 
to  count  them;   it  is  too  bewildering! 

Yet  the  calculation  has  been  made,  and  the  leaves  on 
a  not  very  large  elm  tree  are  said  to  be  about  seven  mil- 
lion, which  would  give  a  surface  of  about  two  hundred 
thousand  square  feet,  or  five  acres! 

From  the  whole  of  these  five  acres  of  green  surface, 
water  passes  off  into  the  air  in  the  form  of  vapor,  to  the 
amount  of  seven  tons  and  three-quarters  during  each 
twelve  hours  of  clear,  dry  weather. 

But  if  this  is  the  quantity  returned  to  the  air  by  a 
single  tree  of  only  moderate  size,  how  large  must  be  the 
amount  received  from  a  wood  or  forest,  containing  hun- 
dred or  thousands  of  trees! 


QUESTIONS  FOR  REVIEW 

1.  Give  the  proportion  of  water  in  the  weight  of  different 
plants. 

2.  Why  do  vegetables  live  and  plants  die  without  water? 

3.  What  is  sap? 


8o  The  Great  World's  Farm 

4.  What   prevents   the   moisture    from  leaving   plants  too 
rapidly? 

5.  What  is  the  difference  between  evaporation  and  trans- 
piration? 

6.  What  conditions  affect  the  number  of  leaf-pores? 

7.  Give   some   idea   of  the  number  and  size  of  the  pores 
in  a  leaf. 

8.  What  is  the  nature  of  the  coating  or  "bloom"  of  leaves? 

9.  Show  how  the  acacia,  eucalyptus  and  cactus  adapt  them- 
selves to  the  climate. 

10.  How  is  this  true  of  plants  in  temperate  climates? 

11.  Why  is  a  pine  forest  less  cool  than  one  of  "leaf-trees"? 

12.  Give  illustrations  of  the  amount  of  water  given  up  by 
plants. 

13.  What  does  this  suggest  as  to  the  value  of  forests? 


CHAPTER  IX 

DESERTS 

From  what  has  been  already  said,  it  is  evident  that 
every  tree,  every  plant,  every  spire  of  grass  indeed,  is  a 
pumping  apparatus  on  a  larger  or  smaller  scale,  by  which 
a  portion  at  least  of  the  water  which  descends  from  the 
clouds  begins  to  mount  up  again  almost  as  soon  as  it  has 
fallen. 

Plants  give  up  to  the  air,  chiefly  by  transpiration 
through  their  leaf-pores,  but  partly  also  by  evaporation 
from  their  whole  surface,  nearly  as  much  water  as  is  taken 
up  by  their  roots — nearly,  but  not  quite — for  as  long  as 
they  are  growing  they  need  some  water  for  the  formation 
of  new  shoots  and  leaves.  The  quantity  is  not  much  in 
itself,  though  water  makes  up  a  large  part  of  the  weight 
of  most  plants.  But  it  is  quite  clear  that,  without  water, 
they  cannot  grow  at  all. 

Provided  a  plant  has  a  plentiful  supply  of  water, 
enough,  that  is,  to  make  up  for  what  it  loses,  it  does  not 
seem  to  matter  how  much  it  transpires.  Some  plants 
thrive  perfectly  well  in  dry  air — where  they  give  off  moist- 
ure constantly  and  rapidly — if  only  their  roots  be  kept  in 
damp  soil,  and  others  thrive  equally  well  in  comparatively 
dry  soil,  provided  the  air  be  damp  enough  to  check 
transpiration  and  allow  them  to  retain  most  of  the  moisture 
they  draw  up.  But  when  once  a  plant  has  thoroughly 
flagged,   the    case    is   different.     Then  nothing    short   of 

8i 


82  The  Great  World's  Farm 

water  supplied  to  the  roots  will  be  sufficient  to  revive  it. 
Damp  air  will  be  of  no  use;  neither  will  the  heaviest  dew 
avail  anything.  The  roots,  and  the  roots  only,  can  fur- 
nish the  necessary  supply. 

Of  course  every  substance — even,  as  we  have  seen,  the 
hardest  rocks — will  absorb  some  amount  of  water  when 
actually  steeped  in  it;  and  so,  if  a  withered  shoot  is  kept 
soaking  in  water,  it  will  absorb  a  certain  quantity  in  time, 
as  any  piece  of  dead  wood  does.  But  leaves  and  stems 
have  little  or  no  power  of  absorbing  moisture  from  the  air. 

This  is  the  general  rule,  to  which  there  are  a  few,  but 
only  a  few,  exceptions;  lichens,  which  have  no  roots,  do 
draw  moisture  from  the  air,  and  would  be  badly  off  if  they 
could  not,  considering  the  bare  rocks  upon  which  they 
grow.  Mosses,  too,  which  grow  where  there  is  little  or 
no  soil,  also  supply  themselves  with  moisture  from  the  air 
to  a  great  extent;  and  so  it  is  believed  do  plants,  such  as 
the  mistletoe,  which  grow  upon  others. 

But  still  the  general  rule  holds  good;  leaves  have  little 
or  no  power  of  absorbing  moisture  either  from  the  air  or 
from  water  poured  upon  them. 

And  yet,  how  the  drooping  leaves  revive  on  a  dewy 
evening,  or  in  a  shower  of  rain,  or  even  under  the  influ- 
ence of  a  shower  from  the  watering-pot !  The  water  can- 
not surely  have  had  time  to  reach  the  roots,  and  then  to 
travel  up  the  stem. 

Water  certainly  does  travel  upwards  with  amazing 
rapidity  in  some  plants,  as  will  be  seen  presently;  but 
when  leaves  revive  on  a  dewy  evening,  or  during  a  shower, 
it  is  not  because  they  have  drunk  in  any  of  these  fresh 
suppUes.  Moisture  is  constantly  passing  up  to  them  in 
larger  or  smaller  quantities  from  below;    but  they  part 


Deserts  83 

with  it  nearly  as  fast  as  they  receive  it  generally,  and 
faster  than  they  receive  it  in  dry  weather.  It  is  the  want 
of  sufficient  moisture  which  makes  them  droop  and  ren- 
ders them  flabby.  But  when  the  dew  falls  on  them  trans- 
piration ceases,  or  nearly  so;  they  are  able  to  keep  nearly 
all  the  moisture  sent  up  to  them,  and  so  they  swell  out 
again  and  stiffen,  and  hold  themselves  up. 

A  similar  effect  may  be  seen  even  in  cut  shoots  which 
have  been  allowed  to  fade,  and  are  then  placed  in  very 
damp  air.  No  moisture  is  taken  up;  quite  the  contrary; 
the  continued  decrease  in  their  weight  shows  that  moisture 
is  passing  off  into  the  air,  little  by  little,  all  the  time;  but 
stem  and  leaves  are  losing  it  very  much  more  slowly  than 
they  did  in  ordinary  air;  and  as  water  from  the  lower, 
older  parts  of  the  stem  continues  to  rise,  as  it  did  before 
the  shoot  was  severed  from  the  tree,  so  the  younger  parts 
at  the  top,  the  leaves  and  buds,  are  refreshed  and  revived. 
Of  course,  this  can  go  on  only  for  a  time;  so  long,  that 
is,  as  any  of  the  original  moisture  is  left  in  the  stem;  and 
when  this  is  exhausted  the  leaves  droop  as  before,  and  at 
last  wither  entirely. 

And  now  to  gain  some  idea,  if  we  can,  of  the  rate  at 
which  water  travels  upwards  from  the  roots  to  the  leaves 
of  a  plant.  This  of  course  varies  enormously  in  different 
plants,  because  some  transpire  so  very  much  more  than 
others;  and  it  also  varies  greatly  at  different  seasons  of 
the  year,  according  as  the  plant  is  growing,  or  putting 
out  buds  and  leaves,  or  not. 

Experiments  made  by  watering  plants  with  colored 
solutions  are  not  very  satisfactory,  because  the  coloring 
matter  may  be  caught  and  entangled,  while  the  water 
moves  on  without  them.     Still,  it  is  interesting  to  learn 


84  The  Great  World's  Farm 

that  in  the  case  of  a  white  iris,  which  was  watered  with 
a  bkie  sohition,  the  white  petals  were  streaked  with  color 
in  from  ten  to  fifteen  hours. 

A  more  trustworthy  experiment  made  upon  a  willow 
seemed  to  show  that  the  water  in  this  case  rose  from  the 
roots  at  a  very  much  more  rapid  rate — thirty-four  inches 
an  hour.  But  the  willow,  having  its  roots  always  in  or 
near  water,  has  no  need  to  be  economical. 

In  a  plant  of  maize,  whose  roots  were  in  earth,  the 
rate  was  much  less,  being  little  more  than  fourteen  inches 
per  hour;  in  a  sunflower  it  was  twenty-five  inches;  but 
in  a  tobacco-plant  it  was  forty-seven  and  one-half  inches 
per  hour.  The  tobacco  transpires  so  freely  that  its  leaves 
droop  as  soon  as  gathered,  and  these  experiments  were 
made  in  such  a  way  as  to  encourage  transpiration  to  the 
utmost. 

In  some  plants  the  sap  rises  with  extraordinary  rapid- 
ity; as,  for  instance,  the  water-liana.  This  is  one  of  the 
many  gigantic,  rope-like  creepers  or  "vines"  of  tropical 
America,  and  owes  its  name  to  the  fact  that  clear,  cool 
water  fit  for  drinking  can  be  obtained  from  its  stem — by 
those,  at  least,  who  know  how  to  proceed. 

These  climbers  mount  up  among  the  trees  far  over- 
head, so  that  to  cut  off  the  top  of  one  is  quite  impossible. 
A  length  of  some  seven  feet  has  to  be  cut  out  where  it  is 
within  reach,  and  this  piece  wih  yield  about  a  pint  of 
water;  but  it  must  be  cut  first  at  the  top,  otherwise,  if 
cut  first  near  the  ground,  almost  the  whole  of  the  water 
will  have  rushed  away  into  the  vine  high  overhead  before 
the  second  cut  can  be  made. 

This  plant,  therefore,  seems  to  dispose  of  a  pint  of 
water  in  less  than  a  minute,  and  almost  all  by  transpira- 


Deserts  8c 

tion,  since  the  quantity  evaporated  and  the  quantity 
required  for  growth  in  one  minute  must  be  exceedingly 
small.  At  this  rate  the  liana  pumps  up  from  the  ground 
sixty  pints  of  water  in  an  hour — seven  hundred  and  twenty 
pints,  or  ninety  gallons,  in  a  day  of  twelve  hours. 

In  early  spring,  when  the  sap  is  beginning  to  rise,  the 
sugar-maple  will  sometimes  yield  as  much  as  seven  or 
eight  gallons  every  day  for  three  weeks,  and  this,  of 
course,  does  not  represent  more  than  a  small  portion  of 
the  water  which  the  tree  has  taken  up,  as  it  is  only  tapped, 
not  drained  of  moisture.  But  the  maple  is  far  outdone 
by  the  black  birch,  another  of  the  American  trees  from 
which  sugar  is  made;  for  one  specimen  of  this  yielded,  in 
four  or  five  weeks,  the  extraordinary  quantity  of  about 
eighteen  hundred  and  ninety  gallons.  And  this,  like  the 
sap  yielded  by  the  maple,  is  only  a  part,  and  a  small  part, 
of  the  moisture  which  the  tree  has  drawn  from  the  earth, 
and  would  in  the  natural  course  of  things  return  to  the  air, 
diminished  only  by  the  small  supply  needed  for  fresh 
shoots  and  leaves. 

But  the  amount  of  water  which  a  plant  takes  up  does 
not  depend  solely  on  the  soil  and  climate  in  which  it 
grows,  but  also  on  the  plant  itself.  There  is  a  wonderful 
difference  in  the  power  which  plants  possess  of  supplying 
themselves  with  food  and  water.  Just  as  one  man  will 
live,  and  even  thrive,  where  another  would  starve,  so  it  is 
with  vegetables.  The  lichen  makes  a  living  off  the  bare 
rock,  where  nothing  else  can  grow;  and  the  ice-plant  car- 
pets some  of  the  most  arid  rocks  of  Greece,  even  after 
months  of  drought,  and  looks,  too,  just  as  deliciously  cool 
as  ever,  its  fleshy  leaves  being  still  covered  with  their 
characteristic  "frosting,"  against  which  the  hottest  sun  is 


86  The  Great  World's  Farm 

powerless.  On  closer  examination  the  coating  of  "frost" 
turns  out  to  be  composed  of  innumerable  globules  of  water 
contained  in  the  surface-cells — the  skin — of  the  leaf.  A 
prick  with  a  needle  shows  that  these  globules  are  just  tiny 
bladders  filled  with  water;  but  this  skin  is  so  exceedingly 
thin,  and  so  perfectly  transparent,  that  it  is  a  mystery  how 
the  plants  manage  to  keep  their  moisture;  and  it  is  often 
no  less  a  mystery  how  they  manage  to  obtain  it  in  the  first 
instance. 

An  English  meadow,  again,  would  wither  and  turn 
brown  if  it  were  left  unwatered  beneath  the  fierce  heat  of 
a  tropical  sun,  but  the  grasses  of  the  Kalahari  Desert  of 
South  Africa  remain  surprisingly  green,  though  they  get 
but  one  or  two  falls  of  rain  in  the  course  of  the  whole 
year.  Sometimes  they  get  no  rain  at  all  for  a  twelve- 
month; but  even  then,  when  they  are  the  color  of  hay, 
they  are  equal  to  hay  of  ordinary  quality  as  fodder  for 
cattle,  and  hence  are  of  course  still  very  valuable.  The 
wonder  is  how  they  manage  to  keep  any  life  at  all,  and 
any  nourishment  in  them,  after  so  many  months  of  burn- 
ing drought. 

In  parts  of  Texas,  where  also  rain  is  quite  the  excep- 
tion, the  grass  is  often  destroyed  during  the  hot  months; 
but  other  green  things  contrive  to  exist,  and  these  supply 
its  place  to  the  cattle.  Timber  is  scarce  in  these  parts; 
but  within  the  last  twenty  years  thickets  of  mesquite 
have  sprung  up,  and  now  cover  miles  of  prairie,  where 
formerly  there  were  none.  And  a  most  valuable  tree 
the  mesquite  is,  not  only  for  fuel,  fences,  and  for  the 
framework  of  houses,  but  for  food.  Its  light  foliage 
takes  the  place  of  grass  during  the  hot  season,  while  its 
beans  supply  the  cattle  with  abundant  food  in  winter;  and 


Deserts  87 

it  is  enabled  to  bear  the  drought  by  the  fact  that  it  has 
huge  roots,  which  weigh  hundreds  of  pounds  when  the 
tree  is  only  a  few  feet  high. 

But  the  prickly-pear  cactus  is  almost  equally  useful,  so 
far  as  the  cattle  are  concerned,  and  it  covers  prairies  so 
vast  that  the  supply  is  simply  inexhaustible.  In  spite 
of  drought,  and  heat,  and  dry  soil,  the  thick,  stem-like 
leaves,  or  leaf-like  stems,  hold  an  enormous  quantity  of 
moisture,  and  when  the  thorns  have  been  burned  off  even 
sheep  can  live  and  grow  fat  upon  it.  For  horses  and 
cows  it  is  split  open,  and  they  eat  out  the  inside,  which  is 
so  succulent  as  to  answer  the  purpose  of  drink  as  well  as 
food.  One  can  hardly  imagine  any  other  way  in  which 
water  could  be  so  successfully  stored  in  these  arid  districts 
as  within  the  thick,  leathery  skin  of  the  cactus. 

But  the  gourd  family  are  almost  as  wonderful  in  the 
way  in  which  they  manage  to  appropriate  and  keep  pos- 
session of  water,  even  under  the  driest  circumstances. 

A  pumpkin  is  all  water,  with  the  exception  of  five  and 
a  half  per  cent  of  its  weight,  and  yet  large  pumpkins  may 
be  seen  growing  in  what  looks  like  nothing  but  sand.  To 
be  sure,  their  thick  rinds  enable  them  to  keep  the  water 
when  they  get  it,  and  sand  is  liberal  in  the  way  of  parting 
with  its  moisture;  but  even  so,  knowing  how  very  watery 
they  are,  it  is  strange  to  see  them  growing  in  such  dry  soil. 
Plants  of  this  kind,  however — gourds  and  melons — are 
especially  characteristic  of  so-called  ''desert"  regions, 
which  are  exposed  to  long-continued  droughts. 

Whenever  there  is  more  rain  than  usual  vast  tracts  of 
desert  land  in  South  Africa  are  covered  with  melons, 
which  provide  food  and  drink  both  for  man  and  beast. 
The  sama,  or  wild  water-melon  of  the  Kalahari,  grows  in 


88  The  Great  World's  Farm 

great  abundance  in  many  parts  of  this  desert;  and  the 
fruit,  which  remains  good  for  a  year  in  dry  seasons, 
affords  the  natives  almost  their  only  supply  of  water  when 
they  are  journeying  across  this  rainless  region.  Evidently, 
therefore,  the  sama  is  able  to  make  the  most  of  its  limited 
opportunities,  and  cannot  only  appropriate,  but  also  keep, 
moisture,  where  most  plants  would  simply  perish  of  thirst. 

Trying  as  are  the  droughts  of  the  South  African  desert, 
they  are  less  severe  than  those  of  Australia,  for  at  all 
events  such  rain  as  does  fall  is  kept,  and  sinks  into  the 
sub-soil,  there  being  no  rivers  to  drain  it  away;  whereas 
in  Australia  the  rivers  quickly  carry  it  off  again.  Even 
here,  however,  some  trees,  and  among  them  the  eucalypti, 
manage  to  store  water  in  their  roots;  and  from  this  supply 
the  natives  were  in  the  habit  of  helping  themselves  in  time 
of  need.  The  long  side  roots  were  laid  bare,  as  much  as 
twenty  or  thirty  feet,  and  divided  into  short  lengths,  from 
which  water  dripped  at  once,  clear,  cool,  and  free  from 
any  unpleasant  taste  or  smell. 

How  the  water  remains  so  cool,  buried  only  from  six 
to  twelve  inches  beneath  the  burning  surface,  is  one  of  the 
many  mysteries  connected  with  the  great  mystery  of  life. 

Water  in  a  pipe,  from  which  there  was  little  or  no 
evaporation,  and  water  in  a  dead  root,  would  speedily 
grow  warm  under  similar  circumstances.  Water  in  a 
porous  vessel  keeps  cool,  indeed,  in  the  hottest  sun, 
because  the  vessel  is  porous,  and  water  is  constantly  pass- 
ing through  it  and  being  turned  into  vapor;  with  the  result 
that  the  air  immediately  surrounding  the  vessel  is  being 
constantly  cooled.  The  water  is  turned  into  vapor  by 
means  of  the  heat  abstracted  from  the  air. 

But  the  water  in  the  roots  of  the  eucalyptus  is  not  kept 


Deserts  89 

cool  by  evaporation;  else,  in  time  of  drought,  it  would  be 
evaporated  altogether.  Besides,  the  juice  of  the  hard, 
leathery-skinned  pomegranate  is  cool  on  the  hottest  day; 
so,  too,  is  that  of  the  melon,  with  its  thick  rind;  and  the 
abundant  juice  of  the  thick-skinned  mango  feels  as  cold  as 
iced  water,  even  under  the  blazing  sun  of  Ceylon;  though 
the  evaporation  from  any  one  of  these  must  be  very  slight 
indeed. 

Moreover,  the  coolness  lasts  only  while  the  fruit 
remains  on  the  plant,  and  disappears  in  a  few  minutes 
after  it  is  gathered.  It  must,  therefore,  be  quite  inde- 
pendent of  evaporation,  and  the  temperature  of  a  living 
plant's  juices  must  be  like  the  temperature  of  the  blood 
in  men  and  animals^  quite  independent  of  climate. 

The  ordinary  temperature  of  the  blood  of  human 
beings  (98°  F.)  remains  the  same  whether  they  live  under 
the  equator  or  in  the  Arctic  regions. 

And  so  it  is  with  plants.  They  are  cold-blooded,  so  to 
say,  and  cold-blooded  they  remain,  even  when  surrounded 
by  hot  air,  as  long  as  they  are  alive.  When  they  are  dead 
their  temperature  soon  rises  or  falls,  according  as  the  sur- 
rounding air  is  hot  or  cold.  But  if  while  alive,  the  tem- 
perature of  their  sap  were  affected  by  climate,  or  by  the 
changes  of  summer  and  winter,  day  and  night,  then  not 
only  would  it  be  constantly  frozen  in  the  Far  North,  and 
not  far  short  of  boiling  in  the  tropics,  but  the  sap  of  an 
acacia  of  the  desert  might  freeze  by  night  and  almost  boil 
by  day — a  sudden  and  violent  change,  which,  as  has  been 
shown,  wears  out  the  very  rocks. 

But  to  return  to  the  ''deserts,"  by  which  we  are  to 
understand  those  regions  where  water  is  scarce,  drought 
frequent,  and  where  vegetation,  though  seldom  or  never 


90  The  Great  World's  Farm 

entirely  absent,  is  more  or  less  scanty,  and  more  or  less 
peculiar,  because  it  is  especially  adapted  to  the  special 
circumstances  of  its  situation. 

The  soil  of  the  desert  may,  or  may  not,  be  poor,  but 
it  is  the  want  of  water  which  renders  these  regions  com- 
paratively barren. 

Well  -watered,  the  Kalahari  Desert  might,  it  is  said,  be 
one  of  the  richest  grazing  lands  in  the  v/orld;  and  the  utter 
barrenness  of  certain  tracts  of  the  Sahara  is  owing  merely 
to  the  lack  of  rain,  for  the  soil  beneath  the  sand  is  actu- 
ally rich,  and  is  not  only  quite  capable  of  supporting  vege- 
table life,  but  is  extremely  fertile  wherever  there  is 
moisture. 

The  other  marked  characteristic  of  desert  lands  is  the 
dearth,  if  not  absence,  of  trees,  and  the  question  we  have 
now  to  consider  is  whether  these  two  characteristics — the 
want  of  water  and  the  scarcity  of  all  vegetation,  but  espe- 
cially of  trees — are  brought  about  the  one  by  the  other. 

Vegetation  cannot  thrive,  though  it  may  manage  to 
exist,  without  a  regular  supply  of  water;  but  does  vege- 
tation bring  rain  or  increase  the  rainfall .'' 

There  is  no  doubt  whatever  that  where  forests  have 
been  recklessly  destroyed  there  the  climate  has  been  most 
seriously  injured.  The  Ceylon  coffee-planters  cut  down 
forests  to  make  more  room  for  their  plantations,  and  many 
of  them  were  ruined  in  consequence.  The  trees  were 
gone,  but  so,  to  a  large  extent,  was  the  rain  also;  and  the 
additional  space  gained  was  valueless,  for  the  coffee  could 
not  grow  for  lack  of  moisture. 

So,  also,  the  destruction  of  the  olive-trees  in  Palestine 
has  diminished  the  rainfall  there,  and  with  the  rainfall 
the  productiveness  of  the  land,  for  centuries  past.     Now 


DATE  PALM  ON  THE  EDGE  OF  THE  DESERT, 


I 


Deserts  91 

that  trees  have  been  planted  again  the  rain  is  said  to  be 
returning. 

So  much,  then,  is  certain:  cut  down  forests  and  you 
will  have  less  rain;  and  though  the  natives  of  Namaqua 
Land,  South  Africa,  attributed  the  great  diminution  in 
their  rainfall  to  the  presence  of  the  missionaries,  others 
had  no  hesitation  in  ascribing  it  to  their  own  wasteful  way 
of  cutting  wood. 

But  though  loss  of  forest  brings  loss  of  rain,  it  is  diflS- 
cult  to  say  precisely  how  the  change  is  brought  about,  and 
whether  rain  is  actually  caused  by  transpiration  or  not. 

Wherever  there  is  vegetation,  be  it  grass  or  be  it  forest, 
there,  as  has  been  shown,  large  quantities  of  water  are 
constantly  passing  off  into  the  air  in  the  form  of  vapor. 
And  the  amount  is  large,  not  merely  considering  the 
means  by  which  it  is  pumped  up,  but  it  is  large  actually; 
very  large,  when  we  compare  it  with  the  amount  of  rain 
which  falls. 

For  instance,  from  the  record  kept  at  Greenwich  it 
appears  that  during  July,  our  wettest  month,  the  average 
fall  of  rain  is  something  under  three  hundred  tons  to  the 
acre,  or  under  three  inches — three  hundred  tons  during 
the  whole  month,  or  less  than  ten  tons  each  day.  But  an 
acre  of  pasture-grass  actually  gives  up  more  than  ten  times 
this  quantity  in  the  course  of  twenty-four  hours — one  hun- 
dred and  six  tons — that  is  to  say,  in  a  single  day  and 
a  night.  So  that  an  acre  of  pasture  which  has  received 
three  hundred  tons  of  rain  in  a  month,  gives  up  more  than 
three  thousand  tons  in  the  same  time. 

The  question  as  to  where  this  immense  quantity  comes 
from  will  have  to  be  considered  later.  At  present  we  are 
concerned  only  with  the  fact  that  so  much  water  is  returned 


92  The  Great  World's  Farm 

to  the  air.  Whether  it  falls  again  on  the  same  spot  is 
another  matter,  and  we  have  no  proof  that  it  does  so.  It 
may  do  so  under  certain  circumstances,  or  it  may  be 
carried  away  by  the  wind  and  fall  elsewhere,  perhaps 
close  by,  or  perhaps  a  long  way  off. 

But  if  the  air  immediately  over  a  certain  district  is 
being  constantly  cooled  by  the  evaporation  day  after  day 
of  large  quantities  of  water,  does  this  produce  no  effect 
upon  the  air  above  .'* 

What  happens  when  water  is  boiled  over  a  fire  ? 
Clouds  of  visible  vapor  rise  from  it,  which  we  commonly 
call  "steam."  They  are  not  properly  steam,  however, 
for  steam  is  invisible.  These  are  clouds,  true  clouds, 
consisting  of  minute  globules  of  water,  steam  made  vis- 
ible, converted  into  water  again  by  coming  into  contact 
with  the  air  of  the  room,  which  is  cooler  than  that  within 
the  kettle. 

As  heat  converts  water  into  gas  or  steam,  so  cold  turns 
it  back  into  water  again.  So  when  the  earth  is  chilled  at 
night  the  moisture  of  the  air  is  also  chilled  on  a  large 
scale,  and  dew  is  formed — first  on  grass  and  leaves, 
because  they  are  cooler  than  the  soil. 

If  this  be  so,  then  when  a  current  of  warm,  moist  air 
comes  in  contact  with  the  cool  air  over  a  forest,  or  over 
acres  of  pasture,  will  not  some  of  its  moisture  be  con- 
densed into  a  cloud,  as  the  steam  from  a  kettle  is  con- 
densed into  a  cloud  when  it  escapes  into  the  air,  and  may 
not  this  cloud  discharge  itself  upon  the  grass  or  the  trees.'* 

Of  course  the  cloud  may  be  carried  away;  but  it  seems 
likely  that,  in  some  cases  at  all  events,  it  will  water  the 
district  above  which  it  is  formed. 

There  is  a  further  question  as  to  whether  trees  actually 


Deserts 


93 


attract  the  clouds  or  not,  and  this  still  waits  for  a  satis- 
factory answer;  but  it  is  certainly  the  popular  opinion  that 
they  do,  and  it  is  a  very  common  thing  to  hear  it  said  that 
the  clouds  have  gone  over  to  a  neighboring  park  or  wood, 
when  the  farmer  would  have  been  better  pleased  that  they 
should  water  his  fields. 

As  we  began  by  saying,  the  subject  is  a  difficult  one; 
but  though  we  may  not  be  able  to  explain  precisely  the 
how,  there  is  no  doubt  at  all  as  to  the  fact  that  the 
presence  or  absence  of  all  vegetation,  not  of  trees  only, 
does  very  greatly  affect  climate,  and  the  climate  in  its  turn 
affects  vegetation. 

For  instance,  Tacitus,  the  Latin  historian,  writing 
some  eighteen  hundred  years  ago,  mentions  that  not  even 
a  cherry  would  ripen  on  the  banks  of  the  Rhine;  and  he 
certainly  would  not  have  believed  that  in  centuries  to 
come  the  same  region  would  have  become  warm  enough 
to  be  famous  for  its  vineyards.  But  in  his  day  forests 
abounded  all  about  the  river,  and  it  is  the  removal,  or 
great  diminution,  of  these  which  has  raised  the  tempera- 
ture. A  similar,  but  in  this  case  disastrous,  result  has 
been  produced  on  the  southern  slope  of  the  Pyrenees, 
where  what  once  were  wide  fertile  tracts,  covered  with 
vegetation,  have  been  turned  into  wastes  by  the  destruc- 
tion of  the  forests  too  recklessly  carried  out. 

Wooded  countries  certainly  seem  on  the  whole  to 
receive  most  rain;  and  the  clearing  away  of  any  kind  of 
vegetation,  be  it  herbage,  brushwood,  or  forest-trees,  may 
be,  and  often  has  been,  attended  by  evil  consequences. 
For  vegetation  protects  the  soil  from  evaporation,  enab- 
ling it  at  least  to  keep  what  water  it  receives;  and  as  this 
accumulates,    springs    or    reservoirs    are    formed,   from 


94  The  Great  World's  Farm 

which  the  plants  in  their  turn  may  derive  suppHes  when 
rain  fails  or  is  insufficient. 

Then  again,  vegetation  preserves  the  soil  from  the 
assaults  of  wind  and  rain,  a  matter  of  no  small  impor- 
tance, especially  in  mountain  regions,  for  as  we  have 
already  seen,  the  earth  on  the  slopes  may  be  clean  washed 
or  blown  away,  and  the  fertility  of  centuries  may  be  thus 
destroyed. 

But  even  this  is  not  all.     The  soil  gone,  what  remains? 

Bare  rock  or  subsoil,  which  is  dried  and  heated  by  the 
sun,  growing  drier  and  therefore  hotter,  till  it  is  quite 
parched.  But  a  dry,  hot  surface  heats  and  dries  the  air 
above  it,  for  hot  air,  being  lighter  than  cold,  rises. 

From  a  wide  expanse  of  dry,  hot  sand,  such  as  that  of 
the  Sahara,  therefore,  there  must  be  a  constant  upward 
current  of  hot  air,  and  this,  again,  must  act  like  a  furnace 
upon  any  moist  current  with  which  it  comes  in  contact. 
The  moisture  has  no  chance  of  condensing  into  a  cloud, 
or  rain,  as  it  might  if  it  met  with  cool  air,  but  is  dis- 
persed— drunk  up  and  evaporated  by  the  hot,  thirsty  air 
from  below.  No  wonder,  therefore,  that  the  Sahara  is  a 
rainless  region. 

The  Island  of  St.  Helena,  again,  is  a  notable  instance 
of  what  man  can  do  in  the  way  of  reducing  a  luxuriant 
garden  to  a  barren  waste,  simply  by  his  ignorant  or  reck- 
less destruction  of  its  natural  vegetation.  When  first  dis- 
covered, the  island,  though  very  mountainous,  and  bounded 
by  tremendous  precipices  rising  some  two  or  three  thou- 
sand feet  above  the  sea,  was  very  fertile,  and  possessed  a 
luxuriant  growth  of  forest.  For  it  is  astonishing  what 
a  thin  film  of  soil  is  enough  for  seeds  to  sprout  in,  if  only 
it  be  moist;   and  it  is  astonishing,  too,  how  little  soil  wiir 


Deserts  or 

suffice  even  for  hardy  evergreens,  birches,  and  other  small 
trees,  whose  roots  often  grow  in  immediate  contact  with 
the  rock.  But  one  thing  is  absolutely  necessary.  If  the 
soil  be  shallow,  moisture  must  be  abundant. 

The  soil  of  St.  Helena  was  rich,  being  formed  by  the 
slow  decay  of  volcanic  rocks,  but  it  was  not  deep,  and 
was  only  kept  in  place  by  the  roots  which  held  it  fast. 
The  Portuguese  brought  goats  to  the  island,  and  by  these 
destructive  animals  the  luxuriant  vegetation  was  in  great 
part  destroyed,  for  they  multiplied  by  thousands.  There 
was  a  wanton  waste  of  wood,  too,  on  the  part  of  the 
human  inhabitants,  though  some  were  far-sighted  enough 
to  predict  that  the  island  would  be  ruined  when  the 
* 'great  wood"  was  destroyed.  And  so,  sure  enough,  it 
was. 

Gradually  the  soil  became  more  and  more  exposed,  and 
whenever  this  was  the  case,  it  was  washed  away  by  the 
violent  rains,  leaving  bare  rock  and  utter  barrenness 
behind.  Still  the  destruction  was  allowed  to  go  on,  until, 
as  the  timber  rapidly  vanished,  not  only  did  the  soil  fol- 
low, but  the  rain  deserted  it  also,  and  the  governor,  taking 
alarm,  reported  that  the  island,  hitherto  abundantly 
watered,  was  beginning  to  suffer  from  drought. 

But  the  authorities — the  island  was  then  in  the  hands 
of  the  Hon.  E.  I.  C. — were  not  to  be  persuaded  that 
there  was  any  connection  between  the  loss  of  trees  and 
the  want  of  rain,  and  returned  for  answer  that  the  goats 
were  more  valuable  than  the  ebony-trees,  and  were  not  to 
be  destroyed.  So  the  goats  stayed,  and  the  ebony-trees 
went;  and  the  general  aspect  of  St.  Helena  became  that 
of  a  dreary,  rocky  desert. 

On  the  other  hand,  a  change  greatly  for  the  better  has 


g6  The  Great  World's  Farm 

taken  place  in  the  region  round  about  the  Suez  Canal. 
Here  there  was  formerly  hardly  a  blade  of  grass  to  be 
seen,  and  the  land  was  a  desert.  But  the  cutting  of  the 
canal  has  brought  water  into  the  midst  of  the  parched 
land;  this  soaks  through  the  sandy  soil,  and  everywhere 
herbage  is  springing  up  along  the  banks.  Rain  is  still 
rare,  but  the  air  is  moister;  for  the  blazing  sun  draws  up 
from  the  canal  large  volumes  of  water,  which,  though  it 
is  only  invisible  vapor  by  day,  is  chilled  and  condensed 
into  water  again  by  the  lower  temperature  of  the  night, 
and  falls  upon  the  thirsty  land  as  a  heavy,  refreshing  dew. 

But  the  very  fact  that  it  is  a  sandy  district  is  in  its 
favor  in  one  way,  for  water  soaks  easily  through  it,  and 
is  thus  brought  to  the  roots  of  all  plants  growing  within 
reach. 

Then,  again,  in  the  Delta  of  Egypt  there  is  much  more 
cultivation  than  there  was  some  years  back.  There  are 
more  corn-fields,  more  pastures,  and  even  little  forests  are 
springing  up,  so  that  its  general  aspect  is  quite  altered, 
and  this  change  is  accompanied  by  a  change  for  the  better 
in  the  climate  also.  Alexandria  has  rain,  even  to  excess; 
and  Cairo,  which  used  to  have  at  most  five  or  six  light 
showers  a  year,  now  has  three  or  four  times  as  much. 
The  increase  in  the  rainfall  seems  to  be  distinctly  trace- 
able to  the  increase  in  the  amount  of  vegetation. 

So  impressed  are  the  Americans  of  the  West  with  the 
connection  between  want  of  trees  and  want  of  rain,, that 
they  now  set  apart  a  day  in  each  year,  which  they  call 
"Arbor  Day,"  and  dedicate  to  the  planting  of  trees. 
Before  this  idea  was  started  there  had  been  such  reckless 
cutting  of  wood  in  the  mountains  and  timber  regions  as 
to  cause  quite  a  dearth  even  of  fire-wood,  especially  in 


Deserts  oy 

what  is  called  the  '*arid  region"  of  the  Western  states. 
Now,  however,  more  than  six  million  trees  are  said  to  be 
growing  on  formerly  barren  lands,  and  Kansas  alone  has 
two  hundred  and  fifty  thousand  acres  of  artificial  forest 
growing  up— a  change  which  it  is  expected  will  so  benefit 
the  whole  region  that  it  will  cease  to  be  arid. 

In  this  land  we  have  little  idea  of  the  magic  change 
produced  in  the  appearance  of  the  landscape  by  rain  falling 
upon  the  hot,  parched  surface  in  southern  latitudes. 
There,  growth  is  so  rapid  that,  in  Ceylon  for  instance,  a 
green  hue  begins  to  color  the  saturated  ground  after  a 
single  day's  rain,  almost  between  dawn  and  sunset,  where 
all  before  was  dreary  brown. 

But  the  change  which  takes  place  in  the  desert  of 
Nubia  is  far  more  wonderful.  During  the  dry  season  not 
a  blade  of  even  withered  grass  is  to  be  seen;  trees  and 
bushes  have  shed  their  leaves — their  very  bark  is  cracked 
by  the  fierce  heat.  The  Atbara — that  mighty  tributary  of 
the  Nile,  to  which  its  yearly  inundations  are  due — has 
altogether  ceased  to  flow,  and  is  converted  into  a  barren 
waste  of  glaring  sand,  four  or  five  hundred  yards  wide, 
interspersed  with  a  few  pools  here  and  there.  And  yet 
the  tremendous  torrents  which  pour  down  into  it  from  the 
Abyssinian  highlands  have  never  ceased  to  flow;  but  the 
whole  of  their  waters,  to  the  last  drop,  have  been  evaporated 
on  the  way  by  the  intense  heat,  or  have  been  absorbed  by 
the  desert-sand  which  has  accumulated  in  the  bed  of  the 
river.  Everything  is  parched,  scorched,  gasping;  not 
only  the  sand,  but  the  air  is  burning. 

Such  is  the  state  of  things  towards  the  end  of  June. 
The  Atbara  is  dead! 

Then  one  night,  when  everything  is  suffocating,  there 


98  The  Great  World's  Farm 

comes,  suddenly,  without  warning  of  any  kind,  a  sound 
as  of  distant  thunder,  a  continuous  roll  and  roar,  which 
means  that  the  river  has  arrived! 

There,  where  there  was  only  sand  the  day  before,  it 
flows  five  hundred  yards  wide,  a  mighty  flood,  and  already 
fifteen  to  twenty  feet  deep ;  for  the  rain  is  pouring  down 
upon  the  great  table-land  of  Abyssinia,  and  it  will  con- 
tinue to  pour  for  two  or  three  months  to  come. 

And  the  change  in  all  the  bare  and  withered  trees  and 
shrubs,  how  rapid  and  how  marvellous  it  is!  In  two 
days'  time  they  show  signs  of  bursting  into  leaf,  having 
previously  looked  as  dead  as  they  do  with  us  in  winter; 
and  as  for  the  mimosas — their  light,  feathery  foliage  is 
already  beginning  to  afford  shade. 

Yet  there  has  not  been  a  drop  of  rain,  or  even  of  dew. 
The  air  no  doubt  is  moister,  for  evaporation  from  this 
wide  expanse  of  water  must  go  on  at  a  tremendous  rate. 
But  at  present  it  is  too  hot  and  dry  to  part  with  a  single 
drop;  and  it  is  from  the  soil  that  the  trees  have  received 
their  fresh  supplies,  so  quickly  does  the  water  soak 
through  the  sand.  But  this  is  not  all  that  they  will  get. 
All  nature  seems  to  expect  a  change,  for  the  wind  is  blow- 
ing from  the  south,  and  rain  is  surely  coming! 

The  natives  of  South  Africa  say  that  the  wind  "smells 
of  green  grass"  when  the  wind  blows  from  a  quarter 
where  rain  has  fallen,  though  this  may  be  hundreds  of 
miles  away;  and  thousands  of  cattle  will  start  off  some- 
times and  travel  immense  distances,  in  the  endeavor  to 
reach  the  fresh  pastures  of  which  the  wind  tells  them. 
So  keen  is  the  scent  of  men  and  animals  in  lands  which 
suffer  from  long  drought. 


Deserts 


99 


QUESTIONS  FOR  REVIEW 

1.  Do  leaves  absorb  moisture? 

2.  What  makes  them  revive  under  rain  or  dew? 

3.  Illustrate  the  rate  at  which  water  travels  from  root 
to  leaf. 

4.  Describe  the  peculiar  qualities  of  the  ice -plant,  the 
grasses  of  the  Kalahari  Desert,  the  mesquite  and  the  prickly- 
pear. 

5.  What  other  plants  are  utilized  in  desert  regions? 

6.  What  reasons  show  that  evaporation  is  not  the  cause  of 
the  coolness  of  these  fruits? 

7.  What  does  this  teach  as  to  the  temperature  of  living 
plants? 

8.  What  reasons  point  to  vegetation  as  one  cause  of  rain? 

9.  In  what  different  ways  does  vegetation  help  to  preserve 
the  moisture  of  a  region? 

10.  Illustrate  this  in  the  case  of  St.  Helena  and  of  Northern 
Egypt. 

11.  Describe  the  effect  of  the  rising  of  the  Atbara  in  Nubia. 


CHAPTER  X 

ROOTS 

Plants,  as  we  have  seen,  need  a  constant  supply  of 
water  for  transpiration  and  for  growth.  They  cannot,  as 
a  general  rule,  take  this  in  by  their  leaves,  and  therefore 
must  take  it  in  by  their  roots;  and  without  water  the  roots 
cannot  take  up  and  supply  to  stem,  branches,  leaves, 
flowers,  and  fruit  that  mineral  matter  without  which  the 
plant  cannot  exist. 

Before  examining  the  way  in  which  the  roots  perform 
their  work  of  supplying  all  parts  of  the  plant  with  liquid 
food,  we  must  briefly  consider  where  the  water  comes 
from. 

For  if,  as  has  been  said,  the  ordinary  rainfall  in  Eng- 
land for  the  whole  month  of  July  is  about  three  hundred 
tons,  and  if  an  acre  of  pasture-grass  transpires  more  than 
three  thousand  tons  in  the  same  time,  it  is  quite  evident 
that  the  demand  far  exceeds  the  supply  from  the  clouds. 
Moreover,  the  grass  does  not  get  even  the  full  benefit  of 
that  which  does  fall,  for  a  very  large  proportion  is  either 
at  once  evaporated  from  the  soil,  or  is  drained  away  into 
ponds,  lakes,  streams,  or  rivers.  Of  the  ram  which  falls 
.in  England  between  April  1st  and  October  ist,  it  has  been 
calculated  that  ninety  per  cent  is  evaporated  from  the  soil 
and  returned  to  the  air.  From  the  air,  however,  the  soil 
again  absorbs  it;  for  though  leaves  do  not  absorb  moisture 
from  the  air,  the  soil  does. 

lOO 


Roots  loi 

We  speak  commonly  of  the  air  as  being  **damp"  or 
**dry, "  as  the  case  may  be;  but  in  point  of  fact  it  is 
never  absolutely  dry,  for  nothing  could  live  in  it  if  it  were. 
It  always  contains  some  amount  of  watery  vapor,  and 
whether  it  be  large  or  small,  soil  which  has  been  dried 
during  the  day  regains  some  degree  of  moisture  by  night 
by  the  simple  process  of  sucking  it  from  the  air.  The 
air  sucks  it  from  the  soil  by  day,  especially  during  sun- 
shine or  dry  wind,  and  the  soil  thus  dried  sucks  it  back 
again  at  night. 

Some  soils  suck  much  more  moisture  from  the  air  than 
others,  and  some  are  also  able  to  keep  it  much  longer 
than  others.  We  all  know  that  a  sandy  soil,  for  instance, 
is  a  dry  soil:  it  takes  some  time  to  grow  really  damp,  and 
it  dries  again  very  quickly.  Indeed,  pure  quartz-sand 
seems  as  if  it  could  not  be  moistened  by  anything  short  of 
rain  or  dew,  being  incapable  of  sucking  any  moisture  from 
the  very  dampest  air. 

A  chalk  or  limestone  soil,  on  the  other  hand,  acts  like 
a  sponge,  and  though  it  may  dry  on  the  surface,  keeps 
its  moisture  a  long  time  within.  The  subsoil  of  the  Kala- 
hari Desert,  already  mentioned,  is  limestone;  and  this  is 
probably  one  reason  why  the  grass  there  is  able  to  remain 
green  so  long  without  rain.  Such  water  as  is  received  is 
kept  for  some  time,  stored  up  in  the  subsoil. 

Of  all  kinds  of  soils,  it  is  those  containing  most  vege- 
table matter  which  take  up  most  moisture,  and  also  remain 
damp  the  longest. 

It  is  a  curious  fact,  however,  that  the  soils  which  are 
least  ready  to  part  with  their  moisture  to  the  air  are  also 
those  which  are  least  ready  to  part  with  it  to  the  roots  of 
plants.     There  may  be  actually  more  moisture  in  vege- 


I02  The  Great  World's  Farm 

table  mold  than  in  sand;  but  the  latter,  at  all  events, 
makes  the  plants  welcome  to  what  there  is,  and  lets  them 
have  almost  every  drop;  while  the  mold  may  have  more 
to  give,  but  also  keeps  back  more.  If  the  two  contained 
an  equal  amount  of  water,  therefore,  plants  would  actu- 
ally be  better  off  for  moisture  in  the  sand  than  in  the 
mold;  but  this  is  not  the  case. 

An  experiment  made  for  the  purpose  of  trying  differ- 
ent soils  with  regard  to  their  readiness  to  give  up  their 
moisture  to  the  roots  of  plants  gave  some  very  interesting 
results.  The  soils  chosen  were  three:  I,  loam;  2,  a  mix- 
ture of  vegetable  mold  and  sand;  and  3,  coarse  sand 
alone;  the  loam  held  two  and  a  half  times  as  much  moist- 
ure as  the  sand,  and  the  sand  and  mold  mixed  held  more 
than  twice  as  much. 

In  these  three  soils  were  placed  some  tobacco-plants, 
which  are  very  thirsty  and  very  watery — four-fifths  water, 
indeed.  Their  broad,  tender  leaves  begin  to  droop  as 
soon  as  gathered  owing  to  their  rapid  transpiration.  The 
sand  gave  up  the  whole  of  the  water  it  contained  with  the 
exception  of  one  and  a  half  per  cent,  and  it  was  not  until 
it  had  reached  this  dry  state  that  the  tobacco  planted  in 
it  flagged;  the  other  plants  flagged  when  the  loam  still 
contained  eight  per  cent,  and  the  vegetable  mold  and 
sand  a  fraction  over  twelve  and  a  quarter  per  cent. 

The  supply  contained  in  the  sand  was  exhausted  first, 
of  course,  because  it  contained  so  much  less  to  start  with; 
but  though  the  other  soils  were  not  nearly  as  dry,  the 
plants  flagged  because  they  could  not  get  hold  of  the  water 
which  they  still  contained. 

Some  plants,  such  as  rice,  grow  equally  well  in  soil  or 
water,  but  most  plants  are  injured  by  having  their  roots 


Roots 


103 


kept  in  water  for  any  length  of  time,  and  are,  as  a  rule, 
in  better  health  when  allowed  to  take  up  the  moisture  they 
need  from  that  which  is  contained,  invisibly,  in  the  pores 
of  the  soil,  when  it  does  not  look  actually  wet  at  all,  and 
no  moisture  could  be  squeezed  out  of  it. 

But  our  main  point  now  is  to  show  that  soil  may,  and 
does,  become  damp  without  rain.  It  may  be  dried  by  sun 
and  wind  by  day,  but  it  makes  up  for  this  by  drawing 
moisture  from  the  air  by  night,  and  it  is  this,  partly, 
which  enables  plants  at  least  to  hve  through  a  time  of 
drought,  though  their  very  stunted  growth  shows  that  the 
supply  has  been  insufficient  for  their  needs. 

The  moisture  which  the  soil  thus  draws  from  the  air 
does  not  remain  on  the  surface,  but  like  the  rain  and  dew, 
sinks  into  the  ground,  penetrating  deeper  and  deeper,  and 
moistening  the  soil  until  it  is  used  up,  or  stopped  by  meet- 
ing either  with  damp  soil,  or  with  soil  or  rock  through 
which  it  cannot  pass.  Rain  falling  upon  a  porous  soil, 
such  as  sand,  or  even  soil  containing  much  sand,  passes 
quickly  through  it  until  it  meets  with  a  bed  of  stiff  clay  or 
rock,  which  prevents  its  going  further;  and  then  what  is 
left,  over  and  above  what  the  soil  has  taken  up,  accumu- 
lates, and  may  in  time  form  a  spring,  or  even  a  sheet  of 
water.  In  some  places  there  are  known  to  be  very  exten- 
sive underground  lakes,  and  these  must  do  much  to  keep 
the  soil  above  them  moist  in  the  absence  of  rain.  The 
springs,  or  underground  streams,  too,  do  the  same,  and 
in  some  cases  they  flow  such  long  distances  that  it  seems 
not  unlikely  the  Kalahari  Desert  may  have  some  such 
subterranean  supply  of  water,  which  enables  the  plants  to 
live  through  the  long,  terrible  drought. 

But  it  may  be  asked,  What  is  the  use  to  the  plants  of 


I04  The  Great  World's  Farm 

water  so  far  beneath  as  to  be  quite  beyond  the  reach  of 
their  roots?  The  answer  to  which  is  that  it  does  not 
remain  beyond  their  reach,  but  is  brought  up  to  them. 

The  water  in  the  soil,  visible  or  invisible,  is  like  a 
stream  which  is  never  at  rest;  it  is  in  constant  motion, 
always  either  rising  or  sinking  according  as  the  surface  of 
the  soil  is  damp  or  dry. 

When  the  surface  is  wet  from  rain,  the  rain  goes  on 
sinking  down  and  down  till  it  is  either  absorbed  by  the  soil 
through  which  it  passes,  or  accumulates  at  some  greater 
or  less  depth  below.  But  when  the  sun  shines  out  again, 
or  a  dry  wind  blows,  the  moisture  of  the  surface  is  evapo- 
rated, the  upper  soil  grows  dry  again,  and  the  moment  it 
is  drier  than  the  soil  below,  the  damp  soil  begins  to  give 
up  its  moisture  to  this  drier  bed  immediately  above  it. 
Thus  the  stream  of  moisture  at  once  begins  to  ascend, 
and  will  continue  to  ascend  until  the  surface  is  wetted 
again;  it  moves,  in  fact,  either  up  or  down,  to  the  drier 
parts  of  the  soil,  whichever  these  may  be,  the  movement 
being  exactly  like  that  of  the  oil  in  the  wick  of  a  lamp;  as 
fast  as  the  oil  is  consumed,  more   rises  to  take  its  place. 

In  time  of  drought  the  soil  may  appear  quite  dry  even 
to  some  depth,  but  as  we  have  seen  in  the  case  of  the 
tobacco  planted  in  sand,  plants  can  continue  to  draw 
moisture  from  the  soil  long  after  all  trace  of  moisture  has 
vanished,  so  far  as  can  be  seen.  To  find  it  at  all  we 
should  have  to  dry  the  soil  by  artificial  heat;  but  it  is 
there,  and  the  plant  manages  to  draw  it  out. 

In  very  long  droughts,  even  the  springs  near  the  sur- 
face may  fail,  all  their  water  being  drawn  away  from  them 
by  degrees;  but  still,  at  a  greater  or  less  depth,  some 
water  there  is,  for  the  deeper  wells  do  not  fail  though 


Roots 


105 


the  shallow  ones  may;  and  unless  this  water  be  buried 
under  some  bed  through  which  it  cannot  pass,  it  will  con- 
tinue to  rise  to  the  surface. 

The  water  which  plants  need,  therefore,  for  growth, 
and  to  supply  the  small  loss  by  evaporation  and  the  large 
loss  by  transpiration,  comes  to  them  from  rain  and  dew; 
it  is  also  very  largely  absorbed  from  the  air  by  the  soil; 
and  the  large  stores  accumulated  in  the  ground  are  also 
drawn  upwards  as  they  are  needed — chiefly,  of  course, 
during  the  spring  and  summer.  In  autumn,  when  growth 
ceases,  transpiration  is  less;  in  winter,  when  the  trees  are 
bare,  there  is  next  to  none,  so  that  they  have  little  need 
of  water.  In  spring  and  summer,  on  the  other  hand,  they 
need  much,  and  receive  it,  in  part,  from  the  accumulated 
stores  of  the  other  months. 

All  the  water  which  plants  transpire — in  many  cases  a 
very  large  quantity,  as  we  have  seen — is  taken  up  by  their 
roots,  and  their  roots  alone.  And  these  roots  we  must 
now  look  at  a  little  more  closely. 

A  root  is  a  very  wonderful  organ,  much  more  wonder- 
ful than  a  passing  glance  would  lead  one  to  suppose. 
And,  indeed,  the  most  important  parts  cannot  even  be 
seen  without  careful  examination. 

The  root  serves  two  purposes:  it  keeps  the  plant  in 
one  place,  enabling  it  to  stand  against  the  wind;  and  it 
collects  from  the  soil  food  and  water  which  the  plant  can 
obtain  in  no  other  way,  and  without  which  it  can  neither 
grow  nor  exist. 

Some  plants  have  a  single  fleshy  root,  like  that  of  a 
carrot,  which  descends  straight  into  the  earth,  and  has  no 
branches,  but  only  a  few  fibers  growing  from  it.  A  car- 
rot needs  a  good  pull  to  uproot  it;    but  an  onion  is  easily 


io6  The  Great  World's  Farm 

lifted  from  the  earth,  as  its  roots  are  only  fibers  growing 
from  the  base  of  the  bulb;  while  a  dock  may  resist  the 
full  strength  of  a  man. 

Water-plants  have  few  roots,  as  their  food  comes  to 
them  already  prepared,  without  their  having  to  search  for 
it;  bog-plants  have  more  roots,  as  they  have  more  work 
to  do;  and  land-plants  have  most  of  all,  as  their  roots 
frequently  have  to  explore  the  earth  for  a  considerable 
distance  in  search  of  food. 

In  a  fertile  soil,  where  there  is  plenty  of  food,  roots 
are  generally  short  and  much  branched.  They  branch 
out,  in  fact,  where  the  food  is  to  be  found.  But  in  a  poor 
soil  they  have  to  go  further  to  find  what  they  need,  and 
are  usually  long  and  slender. 

But  the  mere  mention  of  so  many  feet  gives  no  idea  at 
all  of  the  real  length  of  a  plant's  roots;  for  besides  the 
long  main  roots,  there  are  rootlets  innumerable  branching 
from  them,  and  these  rootlets,  though  they  may  be  mere 
threads  themselves,  are  covered  with  millions  of  hairs, 
generally  so  minute  as  to  be  hardly  visible  without  the 
help  of  a  microscope. 

But  here  again,  as  we  have  seen  in  various  ways  before, 
it  is  the  small,  insignificant  workers  which  are  of  the  most 
importance.  It  is  through  the  younger,  threadlike  root- 
lets, and  through  these  millions  of  minute  hairs,  that  food 
is  chiefly  taken  up;  and  this  is  why,  in  moving  a  plant,  the 
gardener  is  careful  to  keep  a  ball  of  earth  round  its  roots, 
that  the  small,  delicate  rootlets  may  not  be  injured,  and 
its  food-supply  lessened. 

The  root-hairs  are  being  constantly  produced  in  fresh 
millions,  for  each  individual  lasts  but  a  few  days. 

It  is  difficult  in  any  degree  to  realize  what  length  of 


Roots  107 

root  a  plant  possesses,  for  to  do  this  one  must  measure 
not  only  the  main  root,  or  roots,  but  the  branches,  root- 
lets, and  fibers  as  well ;  and  even  then,  the  fringe  of  hairs 
will  have  to  be  left  altogether  unreckoned. 

An  oat  or  barley  plant,  for  instance,  has  roots  several 
feet  long;  but  when  we  say  several  feet,  we  merely  mean 
that  they  stretch  several  feet  downwards  through  the  soil. 
Their  real  length,  if  the  many  roots  are  measured  end  to 
end,  branches  and  all,  is  a  very  different  matter.  A 
barley-plant  grown  in  a  very  small  quantity  of  rich  porous 
soil,  was  found  to  have  a  total  length  of  root  of  one  hun- 
dred and  twenty-eight  feet.  This  measurement  included 
the  fibers,  but  not  the  hairs.  In  loose  soil,  such  as  this, 
roots  can  make  their  way  easily;  but  in  closer  soil,  growth 
is  more  difficult,  and  so  slower,  and  a  plant  grown  in  soil 
of  the  latter  sort  had  roots  only  eighty  feet  long.  Only 
eighty  feet;  but  both  the  eighty  feet  and  the  one  hundred 
and  twenty-eight  feet  were  packed  into  the  fortieth  part  of 
a  cubic  foot  of  soil,  a  quantity  which  would  be  contained 
in  a  box  between  three  and  four  inches  square  and  equally 
deep. 

Of  course,  if  these  roots  had  had  their  liberty  they 
would  have  been  much  less  branched,  and  would  have 
spread  much  further.  They  would,  so  to  say,  have  gone 
much  further  ahead,  without  running  up  so  many  by- 
paths. But  being  prisoners,  they  had  to  make  the  most 
of  what  they  had,  and  so  explored  most  thoroughly  the 
small  space  at  their  command.  Every  one  knows  what  a 
mat  of  roots  and  fibers  there  will  be  when  a  plant  is  taken 
out  of  a  pot  too  small  for  it;  such  a  mat  that  the  earth  is 
often  completely  enveloped. 

Now,  of  course,  it  is  not  natural  for  a  plant  to  grow  in 


io8  The  Great  World's  Farm 

a  confined  space,  with  its  roots  crowded  together  in  this 
way,  and  when  left  to  grow  as  it  hkes,  in  the  open  ground, 
its  roots  often  roam  to  great  distances,  and  therefore 
require  much  more  soil  than  they  make  use  of  as  food. 
The  poorer  the  soil  the  farther  the  roots  spread  in  their 
endeavor  to  find  nourishment,  and  a  maize-plant  in  sandy 
soil  will  send  its  roots  out  a  distance  of  ten  or  fifteen 
feet. 

It  is  supposed  that  only  a  very  small  portion,  perhaps 
a  hundredth  part,  of  the  soil  helps  to  feed  the  plants 
growing  in  it.  And  this  is  probable  enough  when  we 
consider  it;  for  the  soil,  however  fine,  still  consists  of 
solid  particles,  which  the  roots  cannot  swallow;  and 
though  it  is  being  constantly  dissolved  by  water  and  gases, 
the  process  is  a  slovv^  one.  Where  the  soil  is  coarse  the 
process  is  slower  still.  For  as  a  lump  of  sugar  takes 
much  longer  to  dissolve  than  the  same  quantity  of  sugar 
when  reduced  to  powder,  just  so  it  is  with  the  soil;  when 
it  is  fine  the  water  has  a  very  much  larger  surface  to  act 
upon,  and  can  act  more  quickly.  And  this  is  one  reason 
why  finely  ground  soils  are  so  generally  fertile. 

But  this  is  not  the  only  reason;  for  besides  drinking 
in  the  moisture  of  the  soil,  with  whatever  may  be  dissolved 
in  it,  the  roots  do  much  dissolving  on  their  own  account. 
And  it  is  for  this  purpose,  apparently,  that  all,  down  to 
the  smallest  fiber,  and  even  hair,  are  more  or  less  acid. 

What  food  comes  to  them  ready  dissolved  may  be 
brought  from  a  distance  from  the  soil  above  or  below  the 
roots,  but  it  is  brought.  The  particles  of  soil,  on  the 
other  hand,  do  not  move,  and  the  roots  must  go  to  them, 
and  actually  touch  them,  and  that  very  closely,  for  the 
acid  to  be  able  to  act  upon  them.     A  rich  morsel  which 


Roots  109 

is  a  foot,  or  even  an  inch  or  a  half-inch  away,  is  of  no 
use,  except  so  far  as  it  may  be  dissolved  by  water.  The 
roots  can  do  nothing  with  it  unless  some  part  of  them, 
fibers  or  hairs,  are  near  enough  to  get  hold  of  it  and  press 
close  to  it,  as  the  lichen  adheres  to  the  rock. 

And  it  is  this  which  makes  it  so  important  that  a  soil 
should  be  not  only  finely  ground,  but  well  mixed,  so  that 
all  the  ingredients  may  be  within  reach  of  the  roots  of 
each  plant. 

Most  soils  distinguished  for  their  fertility  contain  a  large 
proportion  of  fine  matter,  and  to  this  is  largely  due  the 
extraordinary  productiveness  of  some  of  the  lands  of  Ohio, 
which  have  borne  heavy  crops  of  wheat  and  maize  for 
sixty  years  in  succession.  A  considerable  part  of  the  soil 
here  consists  of  particles  which  measure  from  the  five- 
hundredth  to  the  thousandth  part  of  an  inch  across.  The 
same  thing  is  to  be  observed  in  the  black  earth  of  Russia, 
and  again  in  the  mud  brought  down  by  the  Nile  and  other 
rivers:  all  are  distinguished  for  the  fineness  of  their  par- 
ticles and  their  thorough  mixture. 

Why  is  it  that  a  block  of  granite  is  able  to  support 
only  a  few  lichens  and  mosses  }  Chiefly  because  it  is  a 
block,  into  which  roots  cannot  penetrate.  It  would  not 
make  a  really  fertile  soil  even  if  it  were  crushed  into 
coarse  gravel,  but  it  would  grow  more  than  it  does  now; 
and  if  it  were  ground  to  fine  powder  and  kept  well  watered, 
it  would  grow  even  corn — not  perhaps  good  crops,  though 
even  granites  differ  in  fertility,  but  still  corn — whereas  not 
a  stalk  can  spring  up  while  the  granite  remains  a  block,  no 
matter  how  diligently  it  be  watered. 

By  way  of  testing  this  point,  an  experiment  was  made 
with  some  barley  sown  in  a  soil  consisting  of  pure  feldspar. 


no  The  Great  World's  Farm 

Feldspar  is  that  one  of  the  three  minerals  of  which  granite 
is  composed,  which,  when  finely  powdered  and  washed 
away,  forms  beds  of  clay.  In  this  case  it  was  first  only 
coarsely  powdered,  and  the  barley  grew  to  a  height  of 
fifteen  inches;  moreover,  the  ears  formed,  one  ear  ripened, 
and  two  seeds  were  perfected.  In  the  second  instance  the 
feldspar  was  finely  powdered,  and  the  stalks  were  very 
much  stronger.  One  grew  to  a  height  of  twenty  inches, 
and  perfected  four  seeds. 

Feldspar  alone,  though  a  compound  of  several  elements, 
could  not  in  any  case  produce  a  good  crop;  for  the  stiffest 
clay  soils  under  cultivation  have  been  not  only  well  ground, 
whether  by  ice  or  water,  but  also  mixed  besides,  and  con- 
tain sand  and  other  ingredients. 

It  is,  of  course,  possible  for  the  soil  particles  to  be  too 
fine,  as  they  are  in  pure  clay,  which  is  so  close  in  texture 
as  to  exclude  what  is  as  necessary  to  the  plant  as  food 
and  water,  namely,  air.  A  plant's  roots  need  air  as  much 
as  any  other  part  of  it,  for  they  are  constantly  taking  up 
oxygen,  and  hence  all  specially  fertile  soils  contain  a  large 
proportion  of  sand,  which  makes  them  light  and  porous; 
for  though  fine,  it  is  not  nearly  as  fine  as  the  particles 
composing  the  clay,  and  does  not  turn  into  a  stiff  paste 
when  mixed  with  water. 

In  a  stiff,  heavy  soil  roots  make  their  way  with  less 
ease  and  with  less  rapidity  than  in  a  light,  loamy  one  con- 
taining a  large  proportion  of  sand,  and  therefore  they 
must  needs  collect  food  less  rapidly.  Moreover,  both  air 
and  water  penetrate  a  heavy  soil  less  easily  than  they  do 
a  light  one,  and  hence  not  only  is  the  air  which  the  roots 
need  less  able  to  reach  them,  but  less  water  can  enter 
also,  and  consequently  less  soil  is  dissolved  and  made  ready 


Roots  1 1 1 

for  their  use.  The  "loamy  soil"  which  a  farmer  loves 
contains  from  forty  to  seventy  per  cent  of  sand. 

Here,  again,  we  see  the  great  usefulness  of  earth- 
worms. In  sand  they,  like  the  roots,  can  make  their  way 
so  easily  that  they  have  little  need  to  remove  the  soil  by 
swallowing  it,  the  only  means  at  their  disposal.  But  in  a 
stiffer  soil  they  are  obliged  to  do  this,  and  thus  they  let  in 
both  air  and  water,  to  the  great  advantage  of  the  plants, 
while  they  also  spare  the  roots  much  labor  by  preparing 
for  them  airy  passages,  down  which  they  can  run  with  ease. 

But  though  roots  take  advantage  of  these  ready-made 
channels,  and  are  evidently  all  the  better  for  them,  they 
do  not  let  go  their  hold  on  the  soil,  but  keep  a  close  grasp 
of  it,  lining  the  worm-burrows  with  thread-Hke  fibers, 
which  cling  fast  to  the  sides. 

Roots  coming  in  contact  with  a  piece  of  limestone  will 
leave  upon  it  a  perfect  impression  of  themselves,  even  to 
the  hairs  with  which  they  are  fringed,  showing  how,  like 
the  lichens,  they  have  eaten  their  way  into  the  solid  sub- 
stance. 

How  do  they  do  it.?  We  can  hardly  do  more  than 
conjecture;  but  it  seems  probable  that  the  acid  in  the 
roots  acts  much  as  acid  contained  in  a  bladder  would.  If 
a  glass  tube  is  filled  with  water  made  slightly  acid  with 
vinegar,  and  then  covered  with  a  piece  of  moistened 
bladder  strained  tightly  over  the  mouth,  and  in  contact 
with  the  liquid,  this  will  represent  the  root,  though  the 
resemblance  would,  of  course,  be  closer  if  the  tube  itself 
were  of  bladder.  This,  however,  seems  to  be  the  only 
practicable  way  of  trying  the  experiment.  The  acid  is 
very  weak,  as  the  acid  in  the  roots  is  weak;  but  if  salts, 
such  as  phosphate  of  lime,  and  others  found  in  the  soil. 


Ill  The  Great  World's  Farm 

are  now  strewn  upon  the  bladder,  they  will  in  a  short  time 
begin  to  pass  through  it  into  the  tube,  being  dissolved  by 
the  weak  acid  in  its  pores. 

The  acid  in  the  roots  acts,  it  is  supposed,  in  a  similar 
way,  and  thus  the  dissolved  minerals  are  sucked  in.  But 
as  before  said,  living  things  have  more  power  than  dead 
ones;  so  it  may  well  be  that  roots,  like  lichens,  dissolve 
more  than  the  weak  acid  alone  would  do. 

The  roots  take  up  what  they  themselves  dissolve  from 
the  particles  of  soil  immediately  surrounding  and  closely 
touching  them,  and  also  what  the  water  in  the  soil  has 
dissolved  for  them,  with  the  help  of  carbon  dioxide  and 
other  gases. 

The  water  thus  taken  up — for  what  is  dissolved  by  the 
roots  and  what  is  dissolved  by  water  and  gas  are  taken  up 
together — the  water  thus  taken  up  is  a  very  weak  solution 
of  various  salts — phosphates  and  others — so  weak  that 
it  may  fairly  be  compared  with  ordinary  drinking-water. 

No  water  in  nature  is  or  can  be  perfectly  pure,  as  has 
been  said,  because  it  is  constantly  dissolving  something 
wherever  it  goes.  And  though  even  with  what  the  roots 
have  dissolved  the  solution  is  still  so  weak  as  to  pass  for 
ordinary  water,  yet  it  must  be  borne  in  mind  that  the  roots 
are  constantly  sucking  it  in,  and  that  the  leaves  are  as 
constantly  returning  the  water  to  the  air — only  the  water, 
however.  The  salts  remain  behind  and  accumulate  day 
by  day. 

The  same  sort  of  thing  on  a  vast  scale  goes  on  with 
the  rivers  and  the  ocean.  River  water  is  generally  taste- 
less, though  it,  too,  contains  various  salts  dissolved  in  it. 
This  small  proportion  of  salts  is,  however,  being  con- 
stantly poured  into  the  ocean,  while  the  sun  is  constantly 


Roots  11^ 

taking  away  by  evaporation  almost  pure  water.  The 
salts,  therefore,  accumulate,  and  sea  water  is  salt  and 
bitter  in  consequence. 

The  salts  left  in  a  plant  do  not  usually  make  it  salt  or 
bitter,  because  the  quantity  is  altogether  extremely  minute 
in  proportion  to  the  plant's  size;  and  as  they  are  dis- 
tributed through  the  whole  of  its  substance,  there  is  a 
continual  demand  for  them  while  the  plant  is  growing  or 
putting  forth  fresh  leaves. 

But  if  a  plant  is  stunted  by  drought  it  may  become 
actually  bitter.  A  cabbage,  for  instance,  which  has  not 
reached  perhaps  a  quarter  its  proper  size  for  want  of 
water,  will  be  quite  bitter;  and  the  reason  seems  to  be 
that  the  salts,  which  would  have  been  enough  for  a  large 
cabbage,  are  compressed  into  a  very  small  one.  Or,  in 
other  words,  the  roots  have  not  been  able  to  find  enough 
water  to  dilute  the  food  which  they  have  gathered,  as  well 
as  to  keep  pace  with  the  transpiration  of  the  leaves,  and 
to  allow  of  their  proper  growth. 


QUESTIONS  FOR  REVIEW 

1.  Show  how  soils  vary  in  their  ability  to  suck  moisture 
from  the  air  or  to  keep  it. 

2.  How  do  soils  differ  in  their  readiness  to  give  up  moist- 
ure?    Illustrate. 

3.  How  is  the  surface  soil  moistened  in  time  of  drought? 

4.  How  do  the  roots  vary  in  different  kinds  of  plants? 

5.  Describe  the  character  of  a  root. 

6.  Why  is  it  necessary  that  soil  should  be  both  fine  and 
well  mixed? 

7.  Why  is  clay  a  poor  soil  for  plants? 

8.  What  is  the  character  of  the  water  taken  up  by  the  roots? 

9.  Why  is  the  sea  salt? 


CHAPTER  XI 
FOOD  FROM  THE  SOIL 

It  is  but  a  very  small  part  of  their  food  after  all  which 
plants,  generally  speaking,  draw  from  the  mineral  matter 
of  the  soil  in  which  they  grow;  and  yet  this  small  quantity 
is  not  merely  important,  but  absolutely  necessary.  It  is 
dissolved  by  water  and  gases,  and  by  the  action  of  the 
plant  itself,  and  is  then  taken  up  by  the  roots,  especially 
the  younger,  finer  roots,  and  root-hairs,  by  which  it  is 
passed  on  to  the  stem,  and  so  is  conveyed  to  every  part, 
not  only  to  branches,  leaves,  and  buds,  but  also  to  flowers 
and  fruit.  Every  part  of  a  plant  needs  some  amount  of 
mineral  matter,  and  the  plant  cannot  obtain  it  without 
water,  for  whether  dissolved  by  the  plant's  roots  or  other- 
wise, it  is  in  each  case  taken  up  in  very  diluted  condition; 
so  diluted,  indeed,  that  the  water  containing  it  is  hardly 
to  be  distinguished  from  ordinary  drinking-water. 

The  plant  could  not  be  sufficiently  nourished  by  these 
very  weak  dilutions,  especially  while  it  is  growing,  but  for 
the  fact  that  it  is  constantly  receiving  them. 

Perhaps  one  of  the  most  striking  examples  of  the  way 
in  which  plants  are  fed  by  this  very  weak  food  is  to  be 
found  among  the  sea-weeds.  Many  sea-weeds  contain 
large  quantities  of  iodine,  which,  like  the  rest  of  their 
food,  they  draw  from  the  sea.  With  the  smell  of  iodine 
we  are  all  no  doubt  familiar;  but  if  we  mix  one  part  of 
iodine  with  three  hundred  thousand   parts  of  water  we 

114 


Food  from  the  Soil  1 1  r 

entirely  lose  it;  that  is  to  say,  no  one  of  our  senses  is 
keen  enough  to  detect  it.  We  can  neither  see,  nor  taste, 
nor  smell  it.  But  of  course  it  is  there,  and  we  can  find  it 
again  by  adding  starch,  which  is  turned  to  a  brilliant  blue 
by  coming  in  contact  with  even  this  minute  quantity. 

But  the  iodine  contained  in  sea-water  is  less  even  than 
this — it  is  less  even  than  the  hundredth  part  of  this  infini- 
tesimal amount.  And  yet  the  sea-weed  manages  to 
extract  it.  And  although  plants  take  their  mineral  food 
in  such  weak  dilutions  that  we  cannot  detect  its  presence 
either  by  taste  or  smell,  and  might  be  inclined  to  think 
that  it  can  matter  very  little  what  it  is,  yet  they  are  dis- 
criminating; and  their  roots  have  to  some  extent  the 
power  of  choosing  what  they  will  or  will  not  take  up. 

This  is  evident  from  the  fact  that  plants  growing  side 
by  side  will  take  up  different  food,  or  take  it  in  very  differ- 
ent proportions. 

There  is,  for  instance,  the  common  reed  and  the  com- 
mon species  of  moss,  which  both  grow  in  bogs.  The  soil 
is  dissolved  by  water  and  gases  equally  for  both,  and  both 
take  up  a  good  deal  of  dissolved  flint,  or  silica;  but  the 
reed  takes  up  also  a  very  small  quantity  of  salt,  a  little 
more,  but  still  a  very  small  quantity,  of  iron,  no  soda,  a 
little  magnesia,  and  a  great  deal  of  phosphoric  acid; 
whereas  the  moss,  which  grows  close  by,  takes  very  little 
either  of  phosphoric  acid,  magnesia,  or  salt,  but  some  soda, 
and  much  iron. 

The  same  thing  is  also  true  of  the  farmer's  crops,  and 
it  is  for  this  reason  that  he  varies  them,  not  growing  the 
same  crop  year  after  year,  or  even  two  years  running,  on 
the  same  soil,  lest  it  should  be  exhausted  and  unable  to 
feed  them. 


ii6  The  Great  World's  Farm 

Corn  crops,  for  instance,  take  up  much  flint,  which 
goes  chiefly  to  give  the  hard,  glossy  coating  to  their  stems; 
and  they  want  from  a  fifth  to  a  tenth  part  as  much  potash. 
Turnips  and  beet,  on  the  other  hand,  take  in  httle  flint, 
but  more  hme  and  potash;  and  turnips  and  carrots  will 
use  up  the  suphuric  acid;  while  clovers  want  little  sul- 
phuric acid,  but  much  potash,  lime,  and  soda. 

All  plants  need  more  or  less  of  several  mineral  sub- 
stances, and  even  when  it  is  "less,"  they  cannot  do  with- 
out this  lesser  quantity,  be  it  never  so  small.  When, 
therefore,  we.  say  that  corn  crops  take  up  much  silica,  or 
flint,  it  is  not  at  all  meant  that  they  do  not  take  some 
proportion  of  lime,  potash,  soda,  sulphur,  iron,  and  phos- 
phoric acid  as  well;  for  they  use  them  all,  in  larger  or 
smafler  quantities. 

The  amount  of  each  mineral  taken  up  varies  in  diff"erent 
kinds  of  corn;  wheat,  oats,  barley,  etc.,  have  all  their  special 
needs,  and  so,  as  stated,  have  different  varieties  of  the 
same  kind  of  corn.  More  than  this,  different  plants  of  the 
same  variety  differ  slightly  in  this  respect,  as  if  they  had 
their  own  individual  preferences;  but  the  difference  is 
very  slight,  and  in  plants  of  the  same  species  the  propor- 
tion always  remains  nearly  the  same. 

And  this  is  true,  no  matter  where  the  plant  may  grow. 
If  it  grows  at  all,  its  ash,  that  is,  the  mineral  substances 
which  it  has  taken  from  the  soil,  will  always  be  found  to 
be  pretty  nearly  the  same;  the  proportion  will  be  the 
same,  that  is  to  say,  for  of  course,  in  unfavorable  soil, 
the  plant  may  be  a  dwarf.  Grasses,  for  instance,  which 
are  like  corn  in  taking  in  considerable  quantities  of  silica, 
will  take  up  just  as  much  of  this  when  they  grow  on  the 
chalk  soil  of  the  downs  as  when  they  grow  in  a  soil  con- 


Food  from  the  Soil  117 

taining  much  sand.  Yet  chalk,  pure  chalk,  does  not  con- 
tain a  particle  of  silica. 

As  before  remarked,  however,  such  a  thing  as  a  per- 
fectly unmixed  soil  is  hardly  to  be  found  anywhere.  Even 
on  the  mountains  there  is  rarely  less  than  ten  per  cent  of 
soil  which  has  been  brought  from  elsewhere,  either  by 
wind  or  water,  or  added  to  it  by  animals.  So  it  is  on  the 
downs,  and  the  grass  finds  there  what  it  needs. 

It  would  be  rash  to  say  of  any  plant  that  it  will  not 
grow  on  any  soil  until  it  has  been  tried;  but  plants  cer- 
tainly have  their  likes  and  dislikes  in  this  matter,  though 
sometimes  a  good  climate  will  make  up  for  poor  soil. 

Some  plants  have  such  peculiar  tastes,  or  requirements, 
in  respect  of  soils,  that  they  must  seldom,  one  would 
think,  be  able  to  gratify  them;  and  one  almost  wonders 
where  the  seeds  come  from  when  the  opportunity  for 
growing  does  arrive. 

Some,  for  instance,  are  never  to  be  seen  except  after 
forest-fires;  apparently  because  they  require  wood-ashes 
to  grow  in.  Other  plants  have  similar  likings;  and  it  was 
observed  that  after  the  fires  of  London  and  Copenhagen, 
plants  of  the  same  kinds  grew  among  the  ruins  of  both 
cities. 

It  is  very  remarkable,  too,  what  slight,  and  even  imper- 
ceptible, differences  in  the  soil  will  make  very  great 
differences  in  the  crops  grown  upon  them.  This  is  espe- 
cially noticeable  in  the  case  of  vines.  Tokay  wine,  for 
instance,  cannot  be  made  except  from  grapes  grown  in 
the  one  district  from  which  it  takes  its  name.  The  vines 
may  be  grown  elsewhere,  but  the  wine  is  different.  So, 
too,  in  France;  vineyards  growing  side  by  side,  and  sepa- 
rated only  by  a  narrow  footpath,  having  the  same  aspect, 


1 1 8  The  Great  World's  Farm 

and  apparently  the  same  soil,  and  cultivated  in  precisely 
the  same  way,  yet  produce  v/ine  of  quite  different  qualities 
and  very  different  values. 

Every  crop  takes  away  from  the  soil,  not  one  mineral 
substance  only,  but  several,  in  larger  or  smaller  propor- 
tions; and  the  soil  is  to  this  extent  poorer  than  it  was 
before.  If  the  crop  is  cut  and  carried,  nearly  the  whole 
of  what  it  has  taken  up  is  lost  to  the  soil;  in  the  case  of 
turnips  and  other  root  crops,  the  whole  plant  is  taken 
away,  and  the  loss  is  so  much  the  greater. 

A  meadow  which  is  mown  by  a  machine,  too,  loses 
more  than  one  mown  with  the  scythe,  as  the  machine  cuts 
closer;  and  horses  are  said  to  take  more  from  a  meadow 
than  either  sheep  or  cows,  for  a  similar  reason,  because 
they  are  closer  feeders.  But  where  a  crop  is  consumed 
by  animals,  it  is  not  all  lost  to  the  soil.  On  the  contrary, 
so  much  is  returned  to  it  in  their  droppings,  and  returned, 
too,  with  increased  fertilizing  powers,  that  the  land  is 
actually  benefited,  and  needs  no  other  manure;  whereas 
hay-meadows  cannot  go  on  bearing  crops  year  after  year 
without  being  manured,  or  top-dressed,  to  make  up  for 
their  yearly  loss. 

It  is  a  different  matter,  of  course,  where  the  crops 
grown  by  nature  are  concerned;  for  these,  being  neither 
machine-mown  nor  scythe-mown,  so  far  from  rendering 
the  soil  poorer,  really  do  much  to  enrich  it. 

Herds  of  wild  cattle  may  eat  off  grass  and  herbage,  as 
they  did  for  ages  before  man  came  and  took  possession  of 
their  grazing-grounds,  but  they  manured  the  soil  in  return. 

The  same  is  also  true,  though  in  a  different  way,  of 
the  plants  themselves.  If  they  are  left  alone,  they  return 
to  the   soil  all  that  they  have  taken  from  it,  and  more 


Food  from  the  Soil  119 

besides.  For  they  give  to  it,  also,  that  food  which  they 
draw  from  the  air,  of  which  we  have  yet  to  speak. 

The  roots  of  a  tree  are  constantly  bringing  up  supplies 
from  the  deep  subsoil,  which,  when  the  leaves  fall,  are 
added  to  the  surface-soil;  and  the  ancient  forests  of  North 
America,  after  flourishing  for  ages,  and  producing  enor- 
mous quantities  of  timber,  left  the  soil,  not  impoverished, 
but  so  rich  that  it  was  hardly  exhausted  by  a  whole  cen- 
tury of  wasteful  farming. 

The  ''yellow  earth"  of  China,  a  deposit  of  very  great 
extent,  is  believed  to  consist  very  largely  of  the  ashes  of 
plants,  accumulated  during  more  generations  than  one  can 
attempt  to  realize,  for  in  some  parts  it  is  more  than  fifteen 
hundred  feet  thick. 

It  is  the  long-continued  course  of  this  green-manuring 
which  has  so  largely  contributed  to  produce  the  extraordi- 
nary fertility  of  the  ** black  earth"  of  Russia  and  the  region 
of  Manitoba.  And  so,  too,  with  the  pampas  of  South 
America,  a  still  more  interesting  example,  because  the 
process  is  going  on  under  our  eyes. 

In  the  winter  Captain  Head  found  the  ** thistle"  part 
of  this  region  looking  something  like  a  rough  turnip-field 
intermixed  with  clover,  so  large  and  luxuriant  were  the 
leaves  of  the  thistles — really  wild  artichokes.  In  the 
spring,  the  thistle-leaves  had  spread,  and  had  overgrown 
the  clover,  but  still  had  the  appearance  of  a  rough  crop 
of  turnips.  Less  than  a  month  later,  however,  they  had 
shot  up  in  the  most  surprising  manner,  and  were  in  full 
bloom.  They  were  now  ten  or  eleven  feet  high,  and 
formed  such  a  close,  impenetrable  barrier  on  each  side  of 
the  track  that  nothing  whatever  could  be  seen  in  any 
direction.     The  growth  was  so  amazingly  rapid  that  an 


I20  The  Great  World's  Farm 

army  might  easily  have  been  hemmed  in  unawares  by  the 
thick,  strong  stems. 

Before  the  end  of  the  summer  there  was  another 
change.  The  heads  drooped,  the  leaves  faded,  the  stems 
turned  black  and  rattled  in  the  breeze  until  they  were 
blown  down  by  the  periodical  hurricane,  when  they  quickly 
rotted  away,  and  the  strong,  luxuriant  clover  rushed  up 
again. 

The  artichoke,  as  well  as  its  near  relation,  the  true 
thistle,  requires  a  rich  soil,  and  would  be  an  exhausting 
crop  if  it  were  cut  and  removed,  because  it  takes  so  much 
food;  but  as  the  roots  penetrate  to  a  great  depth,  it  bene- 
fits the  clover,  and  the  clover  in  its  turn  enriches  the  soil 
for  the  thistles. 

Clover  is  found,  indeed,  to  be  such  a  beneficial  crop 
that  farmers  in  America  sometimes  grow  it  in  alternate 
rows  with  wheat,  and  this  is  also  the  only  kind  of  green- 
manuring  commonly  practiced  in  England.  It  is  in  warm 
countries,  where  growth  is  rapid,  that  this  sort  of  manur- 
ing is  chiefly  useful;  and  in  the  Azores,  yellow  lupins  are 
very  frequently  sown  among  the  corn  and  plowed  in  when 
it  is  reaped. 

Lupins  are  plants  which  are  especially  active  in  dis- 
solving mineral  matter;  and  the  same  is  true  of  other 
members  of  the  large  family  of  leguminous  plants  to  which 
they  belong — clovers,  vetches,  beans,  peas.  Moreover, 
not  only  these  but  other  plants  dissolve  more  food  than 
they  need  for  their  own  immediate  use  and  leave  it  in  the 
soil,  making  it  easier  therefore  for  their  successors  to 
find  nourishment. 

This,  then,  is  another  important  service  rendered  by 
the  wild  crops  which  have  grown  for  ages  past  on  what 


Food  from  the  Soil  121 

are  now  the  best  soils  in  the  world  for  the  farmer's  pur- 
poses. Whether  these  crops  be  trees,  or  shrubs,  or  herb- 
age, they  have  not  only  brought  subsoil  up  to  the  surface, 
but  they  have,  at  least  in  some  cases,  dissolved  more  than 
they  have  used,  and  have  left  it  all  ready  for  the  crops 
which  follow  to  make  use  of. 

But  even  this  is  far  from  exhausting  their  very  impor- 
tant list  of  services.  Indeed,  the  most  important  of  all 
has  yet  to  be  mentioned. 

Animals  cannot  live  either  upon  mineral  matter  or  upon 
gases,  though  they  need  both,  until  these  have  been  made 
ready  for  them,  which  they  must  be  in  the  first  instance 
by  vegetables. 

Plants  are  more  independent,  for  they  can  make  use  of 
mineral  matter,  and  of  gases;  but  they,  too,  need  a  little 
organic  matter  as  well,  either  animal  or  vegetable.  Some 
plants  need  more  than  others;  but  no  soil  is  really  fertile 
which  does  not  contain  at  least  some  small  amount.  As 
has  been  shown,  however,  no  soil  is  absolutely  lacking  in 
this  important  ingredient,  for  wherever  plants  have  grown, 
or  animals,  however  lowly,  have  lived,  there  they  have 
left  their  remains. 

Why  plants  should  need  organic  matter  is  another  and 
more  difficult  question,  which  seems  to  be  at  present  un- 
answerable. All  organic  remains,  of  course,  contain  some 
mineral  matter;  but  this  the  plant  can  get  from  the  soil. 
They  all  also  contain  much  carbon;  but  this  the  plant  can  get 
without  their  help  from  the  air.  And  finally,  they  all  con- 
tain nitrogen  in  some  one  or  more  of  its  compounds;  and  it 
is  this  nitrogen  which  the  plant  wants,  and  cannot,  appar- 
ently, get,  in  sufficient  quantity,  except  from  organic  matter. 

There  is  an  abundant   supply  of  nitrogen  in  the  air, 


122  The  Great  World's  Farm 

however,  and  why  plants  cannot  help  themselves  to  it — 
when  they  can,  and  do,  take  up  carbon  dioxide  from  the 
same  source — one  cannot  say;  but  such  is  the  fact.  Both 
are  gases;  and  as  nearly  four-fifths  of  the  air  consists  of 
nitrogen,  there  is  certainly  no  lack  of  it.  However,  the 
plant  takes  the  one  up  by  its  leaves,  as  will  be  seen  in  the 
following  chapter,  and  does  not  take  the  other,  much  as 
it  wants  it. 

All  animal  and  vegetable  matter,  then,  contains  nitro- 
gen; and  as  all  plants,  whether  lichens  and  mosses,  or 
oaks  and  palms,  must  have  some  amount  of  it,  they  most 
of  them  get  it  from  this  source — the  decayed  organic 
matter  in  the  soil. 

But  there  are  others  which  get  it  equally  well  from 
living  matter.  The  mistletoe  and  other  similar  plants  get 
this,  as  well  as  other  food,  from  the  living  trees  or  plants 
upon  which  they  grow.  And  other  plants,  again,  some- 
times turn  the  tables  on  the  animal  world,  and  actually 
devour  living  insects. 

The  plant  called  Venus's  fly-trap  is  one  of  these  insect- 
eaters,  and  a  very  curious  plant  it  is.  Its  leaves  end  in 
two  lobes,  on  each  of  which  are  three  delicate  hairs,  so 
placed  as  to  form  a  triangle,  and  in  such  a  position  that  it 
is  almost  impossible  for  any  insect  alighting  upon  the  leaf 
to  help  touching  them.  As  long  as  the  leaf  only  is 
touched,  no  harm  is  done,  but  if  but  the  tip  of  one  of 
these  magic  hairs  be  touched,  the  leaf  closes  instantly 
upon  the  victim,  and  does  not  reopen  until  it  has  sucked 
it  dry.  The  trap  will  close  equally  upon  a  dead,  dry  fly, 
or  any  other  substance  placed  upon  it,  but  it  reopens 
almost  immediately,  when  the  plant,  by  some  mysterious 
instinct,  discovers  that  the  morsel  is  indigestible. 


Food  from  the  Soil  123 

A  large  blue-bottle  will  be  seized  at  once,  and  squeezed 
so  tight  that  escape  is  impossible.  But  a  meal  of  this  sort 
seems  to  be  very  satisfying,  for  in  one  instance  the  leaf 
did  not  open  again  for  twenty-four  days,  and  when  it  did, 
though  the  dry  remains  of  the  fly  were  removed,  no 
attempt  to  catch  more  was  made  until  several  days  later. 
There  was  a  similar  result  in  the  case  of  caterpillars,  raw 
meat,  and  spiders.  All  are  digested  by  means  of  an  acid 
which  the  leaf  pours  out  upon  them. 

It  is  a  curious  fact,  that  the  dropping  of  water  upon 
the  trap  does  not  make  it  close,  unless  the  sun  is  shining, 
or  has  been  shining  immediately  before,  upon  it.  In  this 
case,  the  plant,  not  being  prepared  for  rain,  seems  to  be 
for  the  moment  deceived.  Rain  usually  comes  when  the 
sky  is  cloudy,  and  then  the  leaf,  knowing  apparently  what 
to  expect,  takes  no  notice.  If  it  closed  for  rain,  it  would 
of  course  often  lose  a  meal. 

One  of  these  plants,  having  six  leaves,  has  been  known 
to  comfortably  digest  twelve  flies,  or  twelve  good-sized 
spiders,  at  once,  one  for  each  lobe,  after  which  it  was 
satisfied  for  some  time. 

The  bladderwort  has  been  seen  to  catch  newly  hatched 
roach  and  also  worms,  by  means  of  its  bladders;  and  the 
butterwort  catches  its  victims  by  means  of  the  sticky 
glands  with  which  its  leaves  are  thickly  covered,  rolling 
up  its  edges  over  them,  and  undoubtedly  eating  them. 

The  various  pitcher-plants  also  feed  upon  the  large 
number  of  insects  drowned  in  their  receptacles,  which  are 
from  two  or  three  to  as  much  as  eighteen  inches  deep,  and 
always  contain  water. 

But  whether  or  no  many  plants  are  actual  flesh-eaters, 
it  is  certain  that  they  all  need  nitrogen;  and  other  food, 


124  ^^^  Great  World's  Farm 

however  abundant,  will  not  be  enough  for  them,  or  enable 
them  to  grow  properly,  if  they  be  stinted  in  this  respect. 
Their  more  usual  way  of  obtaining  it,  however,  is  from 
the  soil,  or  from  the  air;  but  in  neither  case  can  they  take 
the  pure  gas  itself;  it  must  be  in  the  form  of  a  compound 
before  they  can  make  any  use  of  it. 

By  way  of  trying  whether  plants  could  do  without 
nitrogen,  other  than  that  by  which  they  are  surrounded  in 
the  air,  three  pots  were  filled  with  a  soil  of  sand  and  brick- 
dust,  from  which  all  animal  and  vegetable  matter  had  been 
removed.  A  couple  of  sunflower-seeds  were  planted  in 
each,  and  all  three  were  watered  with  pure,  distilled  water, 
containing  no  food  whatever. 

The  plants  in  the  first  pot  turned  out  mere  dwarfs,  as 
was  to  be  expected;  those  in  the  second  were  not  much 
better,  though  they  had  had  a  small  quantity  of  clover- 
ashes  given  them;  but  those  in  the  third  were  almost  as 
large  as  the  finest  specimens  grown  in  the  garden,  for  they 
had  been  supplied  with  a  compound  of  nitrogen,  in  the 
form  of  potassium  nitrate;  and  while  the  two  first  had 
managed  to  get  only  about  the  thirtieth  part  of  a  grain  of 
nitrogen  from  the  air,  these  had  taken  sixty-six  times  as 
much  from  the  soil.  The  quantity  is  still  very  small,  of 
course,  only  two  grains  and  a  fifth;  but  it  strikingly  illus- 
trates the  immense  importance  of  small,  and  even  minute 
quantities,  since  it  made  the  whole  difference  in  the  growth 
of  the  plants. 

The  dwarf  sunflowers  obtained  their  small  fraction  of 
nitrogen  from  the  air;  but  this  is  no  contradiction  to  what 
has  been  previously  said,  for  they  did  not  take  pure  nitro- 
gen, but  ammonia,  which  is  a  compound  of  nitrogen  and 
hydrogen. 


Food  from  the  Soil 


125 


There  is  always  some  very  minute  quantity  of  ammonia 
in  the  air — about  one  part  in  a  miUion — and  there  seems 
to  be  no  doubt  that  plants  can  and  do  take  this  up  by 
their  leaves,  for  they  thrive  all  the  better  when  the  quan- 
tity is  artificially  increased.  But  they  take  it  up  also,  and 
in  larger  quantities,  by  their  roots,  when  it  has  been 
absorbed  by  the  soil,  or  brought  down  to  it  by  rain,  snow, 
and  dew. 

The  quantity  of  nitrogen  thus  washed  down  in  combi- 
nation with  hydrogen  in  the  course  of  the  year  seems  to 
be  from  about  two  pounds  to  nearly  twenty-one  pounds 
per  acre;  but  the  average  is  about  four  and  one-half 
pounds  to  the  acre — four  and  one-half  pounds  spread  over 
an  acre  of  ground!  Considering  that  there  are  seven 
thousand  grains  in  a  pound,  and  that  the  sunflowers,  even 
when  they  had  more  within  reach,  took  up  little  more  than 
a  grain  of  nitrogen  apiece,  perhaps  the  quantity  may  not 
sound  so  very  small. 

But  an  acre  of  wheat,  yielding  twenty-eight  bushels, 
takes  up  about  forty-five  and  one-half  pounds  of  nitrogen; 
while  an  acre  of  clover  uses  one  hundred  and  eight 
pounds! 

And  even  this  does  not  at  all  represent  the  whole  of 
what  is  required;  for  the  roots,  however  many,  cannot 
possibly  be  in  close  contact  with  all  parts  of  the  soil  at 
once,  and  they  can  no  more  make  use  of  all  the  nitrogen 
than  they  can  of  all  the  mineral  matter,  or  all  the  moist- 
ure; so  that  of  this,  as  well  as  of  the  rest,  they  need  much 
more  than  they  can  actually  use. 

An  acre  of  soil,  one  foot  deep,  weighs  some  four  mil- 
lion pounds;  and  just  a  few  pounds  of  nitrogen  equally 
mixed  in  this  would  be  almost   as  difficult  to  find  as  a 


126  The  Great  World's  Farm 

needle  in  a  haystack;   and  even  if  there  were   actually  as 
much  as  the  crop  required,  the  roots  could  not  reach  it. 

A  heavy  wheat  crop  needs,  therefore,  nearly  three 
hundred  pounds  of  nitrogen  to  the  acre,  or  about  six 
times  as  much  as  it  actually  takes  up.  And  this  it  cer- 
tainly cannot  get  from  the  ammonia  in  the  air,  or  from 
that  which  is  washed  from  it  into  the  soil. 

But  when  organic  matter  decays,  whether  it  be  animal 
or  vegetable,  the  nitrogen  contained  in  it  combines  with 
other  gases  to  form  not  only  ammonia,  but  also  nitric  acid. 

Much  of  the  ammonia  streams  off  into  the  air,  but  the 
nitric  acid  remains  and  combines  with  potash,  soda,  lime, 
magnesia,  or  iron,  with  which  it  forms  nitrates.  These 
nitrates  are  easily  dissolved,  and  it  is  from  them  that  the 
plants  obtain  their  nitric  acid — very  much  diluted,  of 
course,  as  is  all  the  food  which  they  take  from  the  soil. 

As  already  remarked,  plants  have  the  power  of  decom- 
posing such  salts,  taking  one  ingredient  and  leaving  the 
other.  The  sunflowers  which  throve  so  well  in  the  ex- 
periment described  were  supplied  with  potassium  nitrate, 
and  from  this  they  were  able  to  extract  the  nitric  acid 
which  they  needed. 

Nitrates  are  very  soluble,  and  in  damp  soil  they  are 
formed  and  dissolved  so  quickly  as  seldom  to  be  visible. 
But  it  is  not  so  in  regions  where  rain  falls  either  at  certain 
seasons  only,  or  very  rarely.  The  most  fertile  soils  of 
Bengal,  for  instance,  are  often  covered  during  the  dry 
season  with  a  white  crust  of  some  of  these  salts,  chiefly 
potassium  nitrate,  otherwise  called  nitre  and  saltpeter. 
The  crust  vanishes  as  soon  as  the  rain  comes,  being  dis- 
solved and  washed  into  the  soil,  which  is  so  rich  as  to 
bear  two  or  three  crops  a  year. 


Food  from  the  Soil  lay 

Wherever  these  nitrates  are  formed,  whether,  as  in 
England,  they  are  dissolved  almost  at  once,  or  whether, 
as  in  dry  lands,  they  accumulate  and  encrust  the  soil,  they 
are  formed  by  the  decay  of  animal  and  vegetable  matter. 
And  what,  it  may  be  asked,  causes  this  decay?  Not  the 
action  of  the  air;  for  in  perfectly  pure  air  organic  sub- 
stances do  not  decay.  The  change  is  brought  about  by 
the  action  of  living  organisms,  invisible,  but  very  potent 
in  their  effects. 

We  have  all  heard  enough  about  "germs"  of  late  to 
know  that  they  swarm  in  the  air;  but  they  also  swarm  in 
all  the  moist  places  of  the  earth.  Some  few  classes  of 
them  are  dangerous  to  man,  and  produce  diseases  of  vari- 
ous kinds;  others  are  not  only  harmless,  but  productive 
of  the  greatest  good. 

All  decay,  fermentation,  or  putrefaction,  whichever  we 
call  it,  is  their  work;  and  when  we  say  ''work,"  all  that 
is  meant  is  their  living,  growing,  multiplying,  which  they 
cannot  do  without  feeding.  There  is  an  immense  variety 
of  them,  and  they  produce  different  results,  according  to 
their  different  modes  of  feeding.  The  yeast  which  is  put 
into  dough,  the  "mold"  which  grows  upon  paste,  or  jam, 
are  all  of  similar  nature,  and  all  produce  alterations  in  the 
substance  which  they  attack.  When  we  like  the  result  of 
these  alterations,  we  call  the  process  "fermentation";  and 
when  we  do  not  like  it,  we  call  it  "putrefaction";  but 
both  are  substantially  the  same,  for  both  are  the  result  of 
decomposition.  Grape-juice,  apple-juice,  and  wort  are 
converted  by  these  "ferments"  into  wine,  cider,  and  beer 
respectively;  and  another  ferment  again  alters  wine  yet 
further,  and  turns  it  into  vinegar. 

It  is  these  living  organisms  which  bring  about  all  decay 


128  The  Great  World's  Farm 

of  animal  or  vegetable  matter,  whether  in  the  soil  or  else- 
where. 

Their  work  in  the  soil  seems  to  go  on  chiefly  in  the 
upper  nine  inches,  and  most  rapidly  when  the  weather  is 
warm  and  damp. 

The  multitudes  of  leaves  drawn  in  by  worms,  the  old 
roots  of  former  crops,  or  green  crops  which  have  been 
grown  only  that  they  may  be  plowed  in — all  are  decayed, 
and  so  converted  into  food,  of  which  the  next  crop  can 
avail  itself. 

As  has  been  more  than  once  remarked,  all  soils  contain 
more  or  less  organic  matter;  but  unless  the  amount  is 
very  large,  as  it  is  in  the  Russian  black  earth  region, 
Manitoba,  and  elsewhere,  not  much  of  the  nitrates  formed 
by  its  decay  will  be  left  in  the  upper  twenty-seven  inches 
of  the  soil  after  a  crop  of  corn  has  been  grown  in  it. 
Organic  matter  there  will  still  be,  but  decay  is  gradual, 
and  nitrates  take  time  to  form;  so  the  farmer  must  sup- 
ply the  want  in  one  way  or  other. 

In  former  days,  till  within  the  last  century  in  fact,  his 
way  of  doing  so  was  simple.  He  merely  plowed  up  the 
field,  and  let  it  alone  to  recover  itself;  in  other  words,  he 
allowed  it  to  lie  fallow. 

And  what  goes  on  in  a  fallow  field?  Generally  speak- 
ing it  is,  or  was,  both  plowed  and  harrowed  repeatedly,  so 
that  the  soil  might  be  exposed  as  much  as  possible  to  the 
action  of  the  air  and  rain,  by  which  the  mineral  matter 
would  be  dissolved  ready  for  the  next  crop.  Then  in  the 
winter  the  soil  would  be  yet  further  broken  up  by  the 
freezing  of  the  moisture  in  its  pores,  wiiich  would  separate 
grain  from  grain,  reducing  it  to  powder  in  a  way  that  no 
plow  or  harrow  yet  invented  can  do.     The  crumbling  of 


Food  from  the  Soil  129 

the  soil  would  make  it  yet  more  easily  dissolved  by  water, 
as  well  as  more  easy  for  roots  to  penetrate;  nor  must  it 
by  any  means  be  forgotten  that  while  the  land  lay  idle  the 
worms  were  busy,  turning  it  over,  also,  grain  by  grain, 
and  enriching  it  as  already  described.  And  though  the 
farmer  did  not  sow  it,  seeds  were  sown  by  the  wind,  and 
a  crop  of  weeds  was  certain  to  spring  up,  whose  half- 
decayed  leaves  the  worms  would  drag  into  their  burrows. 
The  whole  wild  crop,  too,  would  be  plowed  in,  and  with 
the  roots  of  the  farmer's  last  crop,  would  be  gradually 
decayed.  The  soil  when  damp  would  absorb  ammonia 
from  the  air,  and  ammonia  would  also  be  brought  down 
by  rain  and  snow,  and  converted  into  nitric  acid,  which 
would  combine  with  some  of  the  minerals  already  men- 
tioned; and  in  this  way,  as  well  as  by  the  decay  of  the 
organic  matter  left  in,  or  added  to,  the  soil,  a  fresh  sup- 
ply of  nitrates  would  be  prepared. 


QUESTIONS  FOR  REVIEW 

1.  Illustrate  the  fact  that  plants  absorb   mineral  food  in 
very  weak  dilutions. 

2.  Why  does  the  farmer  have  to  vary  his  crops? 

3.  How  differently  is  the  soil  affected  by  the  various  ways 
in  which  the  crops  are  disposed  of? 

4.  What   substance   is  it  which  plants  have  to  get   from 
organic  matter? 

5.  How  do  some  plants  secure  this  from  living  matter?     . 

6.  How  is  the  soil  provided  with  nitrates? 

7.  What  causes  the  decay  of  organic  substances? 

8.  What  processes  go  on  in  a  fallow  field? 


CHAPTER  XII 

LEAVES  AND  THEIR  WORK 

All  the  plant-food  which  we  have  yet  considered  is 
drawn  from  the  soil,  with  the  exception  of  the  minute 
quantity  of  ammonia  taken  in  by  the  leaves  from  the  air. 
But  this  latter  is  far  from  being  all  that  the  leaves  con- 
tribute to  the  food-supply. 

The  roots  furnish  food  from  the  soil — mineral  and 
organic  matter;  and  the  leaves  furnish  food  from  the  air — 
the  carbon,  which  makes  up  about  half  the  dry  weight  of 
a  plant — half  its  weight,  that  is,  when  all  the  water  has 
been  removed  from  it.  Roots  and  leaves,  therefore,  sup- 
ply about  an  equal  amount  of  food. 

But  the  leaves  do  more  than  merely  supply  food;  they 
prepare  it  for  the  whole  plant,  both  that  which  they  them- 
selves take  up,  and  that  which  is  procured  by  the  roots. 
Leaves  are  the  food-manufacturers;  and  it  is  they  which 
combine  the  various  materials,  and  distribute  food  to  the 
several  parts. 

Nitrogen,  the  food  derived  from  organic  matter,  which 
we  have  last  considered,  is  needed  in  some  combination 
or  other  by  all  parts  of  a  plant,  but  especially  by  the 
seed.  No  one  needs  to  be  told  that  grain  is  more  nour- 
ishing than  straw;  but  the  reason  why  it  is  more  nourish- 
ing is  that  it  contains  more  nitrogen,  in  the  form  of 
nitrogenous  or  albuminous  compounds,  commonly  called 
albuminoids,  because  they  resemble  the  albumin,  or  white, 

130 


Leaves  and  Their  Work  131 

of  an  egg.  There  is  albumin  in  the  Hquid  part  of  blood, 
and  there  is  albumin  in  the  seeds  and  juices  of  plants. 
There  is  fibrin  in  flesh  and  in  the  thick  red  part  of  blood; 
and  there  is  vegetable  fibrin,  a  sticky  substance  usually 
called  gluten,  in  flour.  There  is  casein  in  milk  and 
cheese,  and  there  is  casein  in  beans. 

These  various  substances  are  all  jelly-like,  and  are  very 
similar  in  composition,  whether  they  are  obtained  from 
animal  or  from  vegetable  matter.  They  are  called  nitro- 
genous because  it  is  the  nitrogen  they  contain  which  gives 
them  their  especial  characteristics  and  value  as  food;  but 
the  nitrogen  in  them  forms  less  than  a  seventh  part  of 
their  substance,  more  than  half  of  which  consists  of  car- 
bon. In  addition  to  this  large  amount  of  carbon,  most  of 
the  nitrogenous  compounds  contain  sulphur,  besides  hydro- 
gen and  oxygen,  and  most  of  them  phosphorus  as  well. 
They  could  not  therefore  be  formed  without  the  help  of 
mineral  matter  from  the  soil,  and  of  carbon  from  the  air; 
the  nitrogen  being  obtained  both  from  the  nitrates  in  the 
soil  and  from  the  ammonia  in  the  air. 

All  the  corn  crops,  as  well  as  the  clovers,  beans,  peas, 
and  other  leguminous  plants,  require  much  nitrogen,  espe- 
cially when  their  seeds  are  forming  and  ripening;  but  by 
the  time  they  have  done  blossoming,  they  have  taken  up 
all  they  want,  and  it  is  being  prepared  and  compounded 
by  the  leaves,  to  be  gradually  passed  on  by  them  to  the 
growing  seeds  as  they  need  it.  Grass,  therefore,  is  not 
cut  for  hay  until  after  it  has  blossomed,  because  it  then 
contains  most  nitrogen  and  is  most  nutritious.  For  the 
nitrogenous  compounds  are  the  flesh-forming  part  of  all 
food,  animal  or  vegetable. 

They  are  very  much  alike  in  composition,  as  has  been 


132  The  Great  World's  Farm 

said,  and  substances  which  are  closely  similar  may  be 
obtained  both  from  a  beefsteak  and  a  cauliflower;  from 
the  white  of  an  egg  and  from  a  cabbage;  from  milk  curd, 
and  from  peas  and  beans,  of  which  the  Chinese  do  actually 
make  a  vegetable  cheese. 

Quantity  for  quantity,  a  cabbage  is,  indeed,  less  nutri- 
tious than  the  white  of  an  egg,  but  the  cabbage  contains 
a  similar  substance.  It  would,  however,  be  necessary  to 
eat  a  much  larger  weight  of  cabbage  to  obtain  as  much 
flesh-forming  food  as  is  contained  in  an  egg. 

And  then,  again,  though  the  nitrogenous  compounds 
obtained  from  flesh  and  vegetables  are  similar — so  closely 
similar  even  as  to  appear  almost  identical — they  are  not 
absolutely  identical,  and  it  would  be  rash,  therefore,  to 
conclude  that  they  are  equally  nutritious.  For,  if  one 
thing  be  more  plain  than  another,  from  what  has  been 
said  in  the  previous  pages,  it  is  the  immense  importance 
belonging  to  little  things — to  trifles  so  minute  as  almost, 
or  quite,  to  escape  detection. 

Let  us  remember  the  vineyards  growing  side  by  side — 
the  treatment  the  same,  the  soil  so  apparently  the  same, 
that  the  difference  cannot  be  detected^and  yet  the  wine 
from  the  one  is  worth,  and  fetches  in  the  market,  twenty 
times  as  much  as  the  other!  The  vines  being  of  the  same 
species,  and  all  other  things  being  equally  enjoyed  by  both, 
it  follov/s  that  the  difference  in  quality  must  be  caused  by 
some  slight  difference  in  the  soil,  which  is  so  slight  as  to 
be  undiscoverable. 

If,  therefore,  so  slight  a  difference  in  the  vine's  food 
can  make  so  large  a  difference  in  its  produce,  it  seems 
altogether  rash  to  conclude  that  the  cheese  of  beans  is  as 


Leaves  and  Their  Work  133 

nutritious  as  the  cheese  of  milk;  or  that  it  makes  no  dif- 
ference whether  one  dines  on  cauhfiower  or  beef. 

All  plants  do  not  contain  an  equal  amount  of  the  ni- 
trogenous compounds;  and  even  the  same  plant  con- 
tains very  different  quantities  in  different  parts,  and  also 
at  different  stages  in  its  life. 

Leaves  and  stalks  are  less  nutritious  than  seed,  and 
the  seed  itself  is  more  nutritious  when  it  is  ripe,  as  it 
is  then  that  it  contains  the  largest  amount  of  nitrogen. 
Ripe  ears  of  maize,  for  instance,  contain  ten  times  as 
much  nitrogen  as  green  ears;  but  even  then  they  contain 
less  than  either  rye,  oats,  or  wheat,  and  less  than  half  the 
amount  contained  in  peas,  beans,  or  lentils.  Lentils, 
indeed,  are  among  the  most  valuable  of  the  seeds  used  as 
food,  for  nearly  a  fourth  part  of  their  substance  consists 
of  albuminous,  or  nitrogenous,  compounds.  As  for  pota- 
toes, they  are  very  low  down  in  the  scale  of  food,  for  they 
are  chiefly  water,  and  the  amount  of  flesh-forming  food 
which  they  yield  is  only  two  parts  in  a  hundred,  less,  that 
is,  than  meadow-grass  before  it  has  blossomed. 

We  must  now  look  a  little  more  closely  at  the  work 
done  by  the  leaves,  for  it  is  they,  as  has  been  said,  which 
supply  the  plant  with  carbon.  Carbon  is  wanted  for  the 
nitrogenous  compounds;  carbon  is  wanted  for  the  plant's 
skeleton,  and  for  its  wood;  carbon  is  wanted  for  the 
manufacture  also  of  starch,  gum,  sugar,  oils,  acids,  and 
the  various  aromatic  compounds  to  which  plants  and  flow- 
ers owe  their  fragrance. 

And  this  carbon  the  leaves  have  no  difficulty  in  provid- 
ing, so  long  as  the  roots  do  their  part;  but  if  they  fail, 
the   leaves  must  fail,  too.     For  the   plant   is  a  whole,   a 


134 


The  Great  World's  Farm 


body,  of  which  every  part  is  dependent  upon  the  rest. 
But  while  the  roots  can  do  their  work  in  the  dark,  the 
leaves  are  perfectly  helpless  without  light. 

Give  the  plant  light,  however,  together  with  the  proper 
food  which  the  roots  collect  from  the  soil,  and  then  the 
leaves  have  no  difficulty  in  adding  the  carbon  which  is 
their  share. 

And  why,  it  may  be  asked,  should  they  have  any  diffi- 
culty? Since  the  whole  plant  wants  it,  and  has  to  get  it 
through  the  leaves,  surely  it  would  be  more  strange  if  the 
leaves  could  not  find  it,  since  they  live  in  the  air,  where  it  is. 

Perhaps;  but  the  proportion  in  the  air  is  extremely 
small,  though  the  amount  sounds  large;  and  leaves  can- 
not wander  in  search  of  food,  as  roots  do.  The  food 
must  come  to  them,  as  they  cannot  go  to  the  food.  Car- 
bon exists  in  the  air,  combined  with  oxygen,  as  the  gas 
carbon  dioxide,  or  carbonic  acid;  and  there  are  about 
three  billion  four  hundred  million  tons  of  the  gas  in  the 
atmosphere  of  the  whole  globe.  The  figures  convey  little 
to  one's  mind,  but  at  all  events,  the  amount  sounds  com- 
fortably large — sufficient,  at  least,  to  preserve  the  vege- 
table world  from  all  risk  of  a  dearth  of  this  species  of  food. 

And  yet  it  has  been  calculated,  that  if  used  at  the 
present  rate,  the  whole  of  this  enormous  supply  would  be 
exhausted  in  about  a  hundred  years,  after  which  not  so 
much  as  a  blade  of  grass  could  exist  until  the  supply  were 
renewed. 

Let  us  put  it  in  another  way.  The  amount  is  large  in 
itself,  but  it  is  enormously  diluted — so  much  diluted, 
indeed,  as  to  be  hardly  reckoned  at  all;  that  is,  in  speak- 
ing of  the  air,  we  commonly  say  that  it  consists  of  about 
four-fifths  nitrogen  and  one-fifth  oxygen,  leaving  the  car- 


Leaves  and  Their  Work  135 

bon  dioxide  out  of  the  account  altogether.  For  except 
in  confined  spaces,  and  under  special  circumstances,  one 
part  in  twenty-five  thousand  is  all  the  carbon  dioxide  that 
the  air  contains,  so  vast  is  the  space  through  which  the 
gas  is  distributed.  There  is  just  enough  carbon  dioxide  in 
the  air  to  furnish  twenty-eight  tons  to  every  acre  all  over 
the  globe — twenty-eight  tons  of  gas,  or  eight  tons  of  car- 
bon! 

But  an  acre  of  beech-forest  would  use  up  the  whole  of 
this  allov/ance  in  about  eight  years;  and  it  would  not  last 
an  acre  of  bananas  much  more  than  one  year. 

All  plants  do  not,  it  is  true,  use  up  carbon  at  these 
rates;  but  it  is  evident  that  the  supply  needs  pretty  con- 
stant renewing.  And  it  is  renewed  day  by  day,  hour  by 
hour;  nor,  so  long  as  animals  breathe,  and  fires  burn,  and 
vegetable  matter  decays,  is  there  any  danger  that  the  sup- 
ply will  run  short. 

Whenever  carbon  unites  with  oxygen  it  is  what  we  call 
burned,  and  carbon  dioxide  is  produced.  The  carbon  dis- 
appears, but  it  is  not  destroyed — it  has  only  been  made 
invisible  by  combining  with  oxygen.  Whenever,  there- 
fore, animal  or  vegetable  matter  decays,  the  carbon  which 
it  contains  is  slowly  burned,  and  the  gas  passes  off  into  the 
air  as  it  forms,  unless  prevented,  as  it  is,  in  a  great  meas- 
ure, when  produced  underground. 

Again,  when  animals  or  plants  breathe,  the  oxygen 
which  they  inhale  unites  with  and  burns  part  of  the  car- 
bon of  their  food,  and  the  gas  is  breathed  back  into  the 
air.  The  air  we  inhale  contains  but  one  part  in  twenty- 
five  thousand  of  carbon  dioxide;  but  the  air  we  exhale 
contains  much  more — from  three  to  six  per  cent.  Plants, 
however,  breathe  very  much  more  slowly  than  any  warm- 


136  The  Great  World's  Farm 

blooded  animals,  and  give  off  less  carbon  dioxide  in  pro- 
portion. 

Whenever  carbon  is  bu  -ned  by  combining  v/ith  oxygen, 
whether  in  food,  coal,  wocd,  gas,  oil,  candle,  or  in  decay- 
ing vegetable-matter,  there  carbon  dioxide  is  formed.  It 
is  being  constantly  poured  into  the  air,  therefore,  by  men 
and  animals,  by  the  chimneys  of  factories  and  houses,  by 
volcanoes,  and  by  the  soil. 

But  it  is  not  produced  in  anything  hke  equal  quantities 
in  all  parts  of  the  world.  Very  little  is  returned  to  the  air 
above  the  ocean,  and  t'_at  little  chiefly  by  passing  vessels; 
and  as  there  is  more  ocean  than  land  in  the  southern 
hemisphere,  much  less  is  produced  there  than  in  the  north- 
ern hemisphere,  which  is  chiefly  land. 

Then,  again,  the  eastern  hemisphere  is  much  more 
densely  populated  than  the  western,  besides  having,  of 
course,  many  more  factories,  furnaces,  and  engines  of  all 
sorts,  which  are  constantly  burning  carbon.  It  might 
seem  not  improbable,  therefore,  that  some  parts  of  the 
world,  such  as  the  islands  of  the  Pacific,  should  be  at 
times  in  danger  of  not  having  carbon  dioxide  enough  to 
supply  the  wants  of  their  vegetation,  especially  when  we 
consider  that  bananas,  which  need  such  large  quantities, 
form  an  important  item  in  their  crops. 

But  the  fact  is  not  so;  for  the  supply  is  equally  dis- 
tributed. More  fires  are  kept  burning,  and  more  carbon 
dioxide  is  produced  in  winter,  when  the  trees  are  leafless 
and  do  not  want  it,  than  in  the  summer,  when  they  do. 
And  yet  we  are  not  choked  by  it,  or  even  inconvenienced 
by  it,  in  the  winter  months,  so  it  must  be  got  rid  of  some- 
how. For  if  there  were  two  per  cent  in  the  air,  we 
should   have   severe   headache,    and   ten   per  cent   would 


Leaves  and  Their  Work  137 

suffocate  us.  What,  then,  becomes  of  it  ?  Roughly 
speaking,  we  may  say  that  the  carbon  dioxide  produced 
during  the  winter  of  the  north  goes  to  feed  the  vegetation 
of  the  south — the  thistles,  clover,  and  grass,  for  instance, 
of  the  pampas,  which  are  flourishing  in  all  their  luxuri- 
ance while  winter  prevails  with  us.  And  it  goes,  to  some 
extent,  at  least,  because  the  leaves  of  the  southern  hemi- 
sphere draw  it  thither. 

The  ocean  of  air  which  surrounds  the  world  is  not,  it 
must  be  remembered,  a  compound,  but  a  mixture.  If  we 
could  see  it  we  should  find  oxygen,  nitrogen,  carbon 
dioxide,  ammonia,  all  perfectly  mixed,  but  perfectly 
distinct.  The  combination  of  two  gases,  oxygen  and 
hydrogen,  makes  water — a  liquid  entirely  different  from 
both;  but  there  is  no  such  combination  and  alteration  in 
the  gases  of  the  air.  Each  keeps  its  own  character;  but 
though  all  are  of  different  weights,  they  are  so  thoroughly 
and  perfectly  mixed,  that  except  under  special  circum- 
stances, there  is  but  little  appreciable  difference  in  the  air 
of  different  parts  of  the  world. 

Carbon  dioxide  is  the  heaviest  of  these  gases,  and  it  is 
more  than  twice  the  weight  of  the  mixture  of  these  gases 
which  we  call  the  air.  Where  it  is  poured  out  from 
cracks  in  the  earth,  as  it  is  largely  in  some  volcanic  dis- 
tricts, its  weight  keeps  it  down  for  a  time  near  the  ground, 
but  gradually,  in  obedience  to  a  mysterious  law,  it  rises 
and  spreads  through  the  air.  Its  weight  draws  it  down  to 
the  earth,  or  more  correctly  speaking,  the  earth  attracts 
it  to  itself  more  than  it  attracts  either  oxygen  or  nitrogen. 
It  is  heavy,  because  the  earth  attracts  it,  just  as  a  stone 
is  heavier  than  a  feather.     But  it  rises. 

We  should  be  surprised  to  see  a  stone  thrown  from  our 


138  The  Great  World's  Farm 

hand  continue  to  mount  upwards  instead  of  falling  to  the 
ground,  but  this  is  precisely  what  carbon  dioxide  does, 
and  we  can  but  state  the  fact  without  explaining  it. 
Gases,  no  matter  what  their  weight,  are  obliged  to  mix 
one  with  the  other. 

Put  into  a  bottle  first  some  heavy  carbon  dioxide,  then 
some  oxygen,  which  is  lighter,  nitrogen,  which  is  lighter 
still,  and  lastly,  hydrogen,  the  lightest  of  all,  which  is  so 
light  that  it  has  to  be  poured  upwards,  and  though  at 
first  the  heaviest  gas  will  be  at  the  bottom,  before  long 
all  will  be  perfectly  mixed,  and  there  will  be  as  much 
hydrogen  at  the  bottom  as  at  the  top.  Carbon  dioxide 
moves  more  slowly  than  hydrogen,  owing  to  its  weight, 
but  move  upwards  it  will,  and  that  without  any  shaking. 

All,  or  part,  of  the  carbon  dioxide  might,  however,  be 
removed  from  this  mixture  without  affecting  the  other 
gases,  if  a  piece  of  caustic  potash  were  introduced;  for 
this  substance  has  the  power  of  attracting  and  absorbing 
this  particular  gas.  Each  of  the  other  gases  might  also 
be  removed  by  similar  means,  one  by  one  substance,  and 
another  by  another. 

Leaves,  then,  act  upon  carbon  dioxide  in  some  such 
way  as  caustic  potash  does.  They  attract  it  to  them- 
selves and  absorb  it;  but  by  so  doing,  they  are  constantly 
diminishing  the  amount  of  the  gas  in  the  air  immediately 
surrounding  them;  and  as,  according  to  the  law  of  their 
being,  gases  must  mix  equally  one  with  the  other,  more 
carbon  dioxide  flows  in  to  supply  the  place  of  that  which 
is  absorbed.  Streams  of  the  gas  are  therefore  constantly 
flowing  towards  each  leaf,  even  when  the  air  is  still;  when 
there  is  wind  the  whole  air  is,  of  course,  in  motion. 

We  have  now  to  see  what  becomes  of  the  carbon  diox- 


Leaves  and  Their  Work  139 

ide  when  the  leaves  have  taken  it  up.  As  has  been  said, 
in  most  plants  nearly  one-half  the  dry  substance  left  when 
the  water  is  removed  consists  of  carbon,  of  which  char- 
coal is  an  impure  form.  Carbon  enters  into  the  compo- 
sition of  every  animal  and  vegetable  substance,  no  matter 
how  minute.  It  is  to  be  found  in  every  part  of  a  plant 
from  the  root  upwards,  but  especially  in  the  seed.  In 
the  grains  which  we  use  as  food  the  quantity  of  carbon 
amounts  to  some  forty  or  fifty  per  cent  of  the  whole;  and 
though  the  carbon  compounds  are  not,  like  the  nitrogenous 
compounds,  flesh-formers,  they  are  equally  important  as 
fat-formers,  and  as  supplying  fuel  to  maintain  the  heat  of 
our  bodies.  The  carbon  of  our  food  is  oxidized,  burned, 
by  the  oxygen  of  the  air  we  breathe;  heat  is  thus  pro- 
duced, and  the  greater  part  of  the  carbon  is  given  back  to 
the  air  as  carbon  dioxide. 

One  pound  of  wheat  flour  contains  about  nine  and  a 
half  ounces  of  starch,  and  starch  is  a  compound  of  carbon, 
oxygen,  and  hydrogen;  but  it  also  contains  two  ounces  of 
gluten — one  of  the  nitrogenous  compounds — and  half  of 
this  is  carbon;  and  besides  these  it  contains  smaller  quan- 
tities of  sugar,  gum,  and  fat,  and  these  are  all  carbon 
compounds;  so  that  altogether  the  pound  of  flour  con- 
tains some  seven  ounces  of  carbon. 

Some  of  the  palms,  as  the  sago  palm,  use  very  large 
quantities  of  carbon  in  forming  the  starch  of  their  pith: 
one  tree,  for  instance,  often  yielding  the  extraordinary 
amount  of  eight  hundred  pounds  of  starch.  All  the 
sugars,  oils,  gums,  caoutchoucs,  of  the  vegetable  world, 
contain  large  quantities  of  carbon,  and  so  also  do  the 
fibers  of  cotton,  flax,  hemp,  and  others. 

But  as  already  said,  carbon  forms  part  of  the  struc- 


140  The  Great  World's  Farm 

ture  of  every  portion  of  a  plant  from  root  to  seed,  and  it 
enters  largely  into  the  composition  of  the  skeleton,  or 
frame-work,  both  of  stems  and  leaves;  for  a  plant's  skele- 
ton consists  of  fiber,  identical  in  composition  with  the 
fibers  of  the  cotton  and  other  plants  used  for  weaving 
purposes. 

Now  both  the  skeleton  and  the  flesh  of  a  plant,  every 
part  of  it,  indeed — roots,  stems,  leaves,  flowers,  fruit, 
seed — consists  either  of  a  single  cell,  or  of  an  assemblage 
of  cells,  which  may  be  compared  with  the  cells  of  a  honey- 
comb, except  that  they  vary  extremely  in  size  and  shape. 

Some  cells  are  so  minute  as  to  be  altogether  invisible 
to  the  naked  eye;  as  for  instance,  the  spores  of  lichens 
and  fungi,  the  "germs"  already  mentioned,  and  certain 
minute  water-plants,  each  and  all  of  which  consist  of  a 
single  cell,  filled,  like  the  honey-cells,  with  more  or  less 
fluid  contents. 

But  the  cells  in  the  flesh  of  a  lemon  are  gigan:ic  by 
comparison,  being  half  an  inch  long;  the  cells  of  fibers 
are  often  much  longer  than  this,  and  there  are  cells  of  all 
sizes  between  these,  the  most  usual  size  being  from  y^Vo 
to  -j^-Q  of  an  inch  across.  Cells  are  of  almost  every  pos- 
sible shape,  too — globular,  square,  six-sided,  twelve-sided, 
or  quite  irregular,  with  their  outlines  beautifully  zigzagged 
or  waved.  But  whatever  their  shape  and  size,  their 
walls,  thick  or  thin,  are  composed  of  the  skeleton  material 
mentioned  above,  which  is  called  after  them  "cellulose." 

This  material,  like  cotton  and  other  fibers,  is  composed 
in  great  measure  of  carbon,  and  as  all  plants  increase  in 
size  by  the  multiplication  of  cells,  it  is  evident  that  they 
could  not  grow  at  all  in  air  containing  no  carbon  dioxide. 
Neither  can  they  grow   if  deprived  of   their  leaves,   for 


Leaves  and  Their  Work  141 

these  are  the  chief  manufacturers  of  cellulose  and  other 
food.  A  tree  stripped  of  even  half  its  leaves  will  be 
unable  to  make  much  wood,  though  it  may  manage  to 
live. 

The  skin  of  a  leaf  usually  consists  of  a  single  layer  of 
cells,  not  green,  but  colorless  and  transparent,  and  beneath 
these  are  other  cells  containing,  besides  other  things, 
'* leaf-green,"  or  coloring  matter.  It  is  in  these  lower 
cells  that  the  manufacture  of  the  plant's  food  is  carried 
on;  and  though  the  process  cannot  be  explained,  one  or 
two  facts  are  certain — it  cannot,  in  most  plants,  go  on 
without  light,  or  in  any  without  the  leaf-green. 

The  gases  of  the  air  are  able  to  pass  through  the  cell- 
walls,  both  in  and  out.  It  must  not  be  forgotten  that 
plants  need  air  for  breathing,  as  well  as  carbon  dioxide  for 
food;  and  though  they  breathe  as  well  as  feed  by  means 
of  their  leaves,  the  two  processes  are  quite  distinct. 

What  the  plant  does  with  the  carbon  dioxide  is  to  sepa- 
rate the  carbon  and  keep  it,  and  to  let  go  most  of  the 
oxygen.  The  two  have  to  be  torn  asunder,  and  this  is 
done  in  the  cells  containing  leaf-green.  But  the  leaf-green 
itself  cannot  be  developed  either  without  light,  or  without 
iron;   and  when  developed  it  cannot  act  in  darkness. 

For  the  supply  of  iron  the  leaves  are,  of  course,  de- 
pendent upon  the  plant's  roots,  and  if  the  roots  cannot 
find  it,  the  leaves  and  young  stems  remain  yellow  or 
colorless.  Compounds  of  iron  are,  however,  so  very 
general  in  all  the  rocks  composing  the  earth's  crust,  that 
it  is  almost  impossible  to  find  any  soil  quite  without  them. 

But  the  iron  may  be  taken  away  by  artificial  means, 
and  when  this  is  done  the  leaf-green  turns  yellow,  as 
human  beings  do  when  their  blood  contains  too  few  red 


142  The  Great  World's  Farm 

particles,  and  for  precisely  the  same  reason.  Both  stand 
in  need  of  iron.  Iron  oxide  is  reddish  when  it  contains 
the  full  amount  of  oxygen  possible,  and  green  when  it 
contains  less.  Give  the  plant  iron  and  keep  it  in  the  light, 
and  the  grains  of  leaf-green  at  once  begin  to  turn  their 
proper  color,  and  tiny  grains  of  starch  form  within  them. 

A  very  little  light,  barely  enough  to  read  by,  will  be 
sufficient  to  make  a  plant  begin  to  turn  green,  but  not 
sufficiently  green  to  enable  it  to  separate  the  carbon;  and 
therefore  in  dim  light  no  starch  grains  can  be  formed.  In 
ordinary  daylight,  however,  whether  the  sun  be  shining 
directly  upon  the  plant  or  no,  these  starch-grains  are  being 
continually  produced;  but  the  brighter  the  light  the  more 
briskly  the  manufacture  goes  on,  up  to  a  certain  point — 
provided,  that  is,  that  the  air  contains  carbon  dioxide 
wherewith  to  furnish  the  necessary  supply  of  carbon.  If 
it  does  not,  no  starch,  of  course,  can  be  formed,  no  mat- 
ter how  bright  the  light,  or  how  green  the  leaf-green. 

But  all  air,  unless  artificially  deprived  of  it,  contains 
enough  to  furnish  what  the  plant  requires  in  this  respect, 
thanks  to  the  supplies  which  are  being  constantly  furnished 
to  it.  This  is  taken  up  not  only  by  the  leaves,  but  by  all 
the  green  parts  of  a  plant,  leaves,  buds,  stems,  and  fruit, 
so  long  as  these  remain  green;  for  it  is  only  in  the  cells 
which  contain ieaf-green  that  starch  is  manufactured  from 
the  gas.  These  green  cells  lie  immediately  underneath  the 
thicker-walled  but  transparent  cells  of  the  surface  which 
compose  the  skin;  and  through  the  skin  the  gas  finds  its 
way  into  them. 

The  leaf-pores,  by  which  water  escapes,  are  openings 
in  the  skin  formed  by  two  curved,  lip-hke  cells,  which 
gape  open  in  hot,  bright  weather,  and  close  more  or  less 


Leaves  and  Their  Work 


143 


in  rain,  damp,  and  darkness;  and  it  is  when  they  open 
most  widely  that  the  manufacture  of  food  goes  on  most 
briskly.  For  it  is  then  that  most  carbon  is  separated,  and 
most  food  is  pumped  up  from  the  roots,  as  that  is  the 
time  when  the  plant  transpires  most,  and  in  this  way  both 
kinds  of  food  are  received  together.  When  there  is  much 
transpiration,  and  water  containing  dissolved  food  is 
pumped  up  rapidly,  then  also  much  carbon  is  received, 
and  vice  versa. 

Such  plants  as  the  cactus,  which  have  no  leaves,  very 
few  pores,  and  skin  so  thick  and  leathery  that  evaporation 
is  prevented,  transpire  very  little,  and  grow,  in  consequence, 
very  slowly.  The  tall  torch-thistle  cactus  of  Mexico  is 
said  to  take  some  hundreds  of  years  in  attaining  its  full 
size;  whereas  the  thin-leaved  gourd  of  the  East  is  noted 
for  its  very  rapid  growth. 

How  the  food  from  the  soil  and  the  food  from  the  air 
are  combined,  and  distributed  from  the  leaves  to  all  parts 
of  the  plant,  is  unknown;  but  from  them  each  part  does 
receive  its  due  share  of  nourishment,  one  more  of  this 
sort,  one  more  of  that. 

But  without  the  leaves  no  food  can  be  prepared,  except 
where  the  stems  take  their  place;  and  without  light  the 
leaves  have  no  power  to  act.  Hence  the  plant's  whole 
life  depends  upon  the  sun. 

In  the  autumn,  when  the  plant  has  finished  growing, 
no  more  leaf-green  is  formed,  and'  the  leaves  begin  to 
change  color;  for  instead  of  manufacturing  food,  they 
are  giving  up  their  own  stock  to  feed  the  young  fruit. 

Some  plants,  such  as  lichens,  copper-beeches,  and 
others,  might  be  supposed  to  possess  no  leaf-green, 
because  it  is  not  visible;  but  they  have  it  all  the  same;  it 


144  T"h^  Great  World's  Farm 

is  merely  concealed  from  view,  hidden  by  other  coloring- 
matter. 

But  some  plants  never  have  any  leaf-green  under  any 
circumstances,  and  therefore,  being  non-manufacturers, 
they  have  to  live  by  the  labor  of  others.  Among  these 
are  the  fungi,  which  grow  and  feed  entirely  upon  organic 
matter,  animal  or  vegetable,  and  are  independent  of  the 
light.  Mushrooms,  for  instance,  may  be  grown  in  cel- 
lars; toadstools  spring  up  in  the  night;  for  their  food  of 
all  kinds — mineral  food,  nitrogenous  compounds,  carbon 
compounds — has  been  made  ready  for  them  in  the  light, 
by  the  dead  vegetable  matter  upon  which  they  grow. 
Perhaps  it  is  the  fact  of  their  not  having  any  work  to  do 
which  enables  them  to  grow  with  such  extraordinary 
rapidity,  as  they  devote  all  their  energies  to  feeding  and 
increasing  in  size.  The  cells  of  the  puff-ball,  for  instance, 
multiply  at  the  rate  of  three  or  four  hundred  million  in 
an  hour,  and  the  plant  will  attain  the  size  of  a  large  gourd 
in  a  few  days.  The  curious  brown  bird's-nest  orchis  is 
another  plant  which  has  no  leaf-green,  cannot  provide  its 
own  food,  and  lives  upon  dead  vegetable  matter. 

But  there  are  other  plants  devoid  of  leaf-green,  which 
prey,  not  on  the  dead,  but  on  the  living;  sucking  their 
juices,  and  profiting  by  their  labors  in  earth  and  air. 
Among  these  may  be  mentioned  the  broom-rape,  a 
brown,  uncanny-looking  plant,  which  attaches  itself  to 
the  roots  of  living  plants,  clover,  and  others,  and  draws 
all  its  nourishment  from  them. 

In  one  way  or  another,  then,  all  plants  obtain  carbon; 
and  when  they  have  to  do  it  by  their  own  exertions  they 
must  have  leaf-green,  and  they  cannot  usually  have  leaf- 
green  without  light,  or  in  any  case,  without  iron. 


Leaves  and  Their  Work  145 

But,  it  may  be  said,  seeds,  most  of  tliem,  begin  to 
grow  in  darkness,  underground,  and  so  do  bulbs;  and  they 
are  usually  pale  yellow  at  first.  If  they  have  no  leaf- 
green,  as  they  evidently  have  not,  then,  if  cells  cannot  be 
multiplied  without  carbon,  and  carbon  they  cannot  get  for 
want  of  this  leaf-green,  how  do  they  manage  to  grow? 

In  the  same  way  that  other  plants  do  which  are  also 
without  leaf-green.  They  make  use  of  the  carbon  stored 
by  others;  that  is  to  say,  they  live  for  a  time  seedlings, 
upon  the  material  stored  in  their  seeds — bulbs,  upon  the 
material  stored  in  the  bulbs,  which  are  buds,  not  roots — 
all  of  which  has  been  prepared  by  means  of  leaf-green, 
and  in  the  light. 

In  the  case  of  bulbs,  the  leaves  go  on  collecting  food 
long  after  the  plants  have  done  flowering,  in  readiness  for 
the  blossoms  of  the  next  spring;  and  if  the  leaves  are  cut 
off  before  they  have  finished  their  work,  the  bulbs  shrivel, 
and  have  not  the  means  of  supplying  next  year's  blossoms 
at  all.  The  autumn  crocus  comes  up  and  blossoms 
without  its  leaves,  but  it  is  dependent  upon  them  for  the 
means  of  putting  forth  its  blossoms,  for  the  leaves  have 
been  busy  months  before,  in  the  spring,  storing  the  neces- 
sary material  in  the  bulbs. 

Seedlings,  in  like  manner,  when  first  they  germinate 
under  the  soil,  before  they  are  provided  with  leaf-green, 
live  upon  the  food  stored  up  within  them;  but  if,  when 
this  is  exhausted,  they  are  still  kept  in  darkness,  they  will 
not  only  remain  yellow,  but  will  lose  instead  of  gain 
in  weight,  and  that  though  their  roots  may  be  busy  col- 
lecting food  from  the  soil. 

But  why,  it  may  be  asked,  should  they  lose  in  weight? 
Without  carbon  they  cannot,  of  course,  use  the  food  from 


146  The  Great  World's  Farm 

the  soil;  they  cannot  grow;  but  provided  they  have  water, 
why  should  they  not  remain  as  they  were?  What  are 
they  doing  to  make  them  lose  weight? 

Well,  they  are  doing  just  what  all  living  things  do,  and 
must  do,  if  they  are  to  remain  living;  they  are  breath- 
ing— breathing  as  animals  do,  though  they  have  no  lungs, 
and  though  they  breathe  very  much  more  slowly;  that  is 
to  say,  they  are  taking  in  air. 

In  breathing,  as  has  been  said,  part  of  the  oxygen  of 
the  air  inhaled  combines  with  and  burns  up  part  of 
the  carbon  taken  in  as  food,  converting  it  into  the  gas 
carbon  dioxide,  which  is  breathed  back  into  the  air. 
Warm-blooded  animals  breathe  much  more  vigorously 
than  plants  do,  but  the  process  is  the  same  in  both. 

Plants,  however,  breathe  more  or  less  through  their 
whole  surface,  though  chiefly  through  their  leaves,  and 
from  the  leaves,  the  air  finds  its  way  to  every  part. 

Probably  the  breathing  of  plants  may  be  fairly  com- 
pared with  the  slow  breathing  of  cold-blooded  animals; 
but  though  feeble  it  is  always  going  on,  night  and  day,  in 
light  and  in  darkness,  though  more  vigorously  in  light; 
and  therefore,  as  the  stock  of  carbon  is  gradually  burned 
or  oxidized,  and  breathed  out,  if  it  is  not  replenished  it 
must  be  gradually  exhausted,  and  the  plant  must  lose 
weight. 

To  prove  this,  two  beans  of  nearly  equal  w^eight  were 
planted  at  the  same  time,  one  being  kept  in  the  dark,  the 
other  in  the  light.  At  the  end  of  twenty-six  days  it  was 
found  that  the  seedling  kept  in  darkness  weighed  more 
than  a  third  less  than  the  original  bean,  and  the  other 
weighed  more  than  a  third  more.  The  one  had  breathed 
away  some  of  the  carbon  contained  in  the  thick  seed-leaves 


Leaves  and  Their  Work  14-7 

without  being  able  to  extract  any  from  the  air  to  feed 
upon,  while  the  other  had  obtained  food  enough  for  grow- 
ing and  breathing,  too. 

There  is  some  difference  in  the  breathing  of  the  leaves 
and  the  blossoms  of  a  plant.  The  blossoms  breathe  faster 
than  the  leaves,  especially  when  they  are  just  opening; 
and  they  are  therefore  slightly  warmer — in  some  cases, 
indeed,  so  warm  that  the  heat  may  actually  be  felt!  And 
the  same  is  true  of  sprouting  seeds  when  there  are  many 
together.  The  sprouting  barley,  for  instance,  from  which 
malt  is  made,  gives  off  quite  a  high  degree  of  heat. 

As  the  plant,  like  the  animal,  must  breathe  in  order  to 
live,  it  must  needs  have  a  constant  supply  of  air  for  breath- 
ing, as  well  as  feeding,  purposes.  And  this  air  is  neces- 
sary, more  or  less,  not  only  for  leaves  and  blossoms,  but 
for  all  parts,  including  stems  and  roots.  It  breathes 
through  all,  though  chiefly  by  its  leaves  and  blossoms  and 
the  roots  are  always  breathing  out  carbon  dioxide  into  the 
soil.  If  the  soil  be  too  close,  or  baked  on  the  top,  the 
roots  cannot  get  enough  air  to  breathe  properly,  and 
the  plant  is  sickly.  And  the  same  thing  happens  when 
soil  is  piled  up  round  the  stem,  for  the  air  is  then  kept 
away  both  from  it  and  from  the  roots,  and  many  a  tree 
has  been  killed  in  consequence. 

QUESTIONS  FOR  REVIEW 

1.  Name  some  of  the  most  common  nitrogenous  substances. 
Why  are  they  so  called? 

2.  W^hy  is  it  rash  to  conclude  that  they  are  equally 
nutritious? 

3.  What  is  the  most  nutritious  part  of  the  plant,  and  when? 
Illustrate. 


148  The  Great  World's  Farm 

4.  For  what  does  the  plant  need  carbon? 

5.  How  is  carbon  supplied  to  the  air? 

6.  What  gases  make  up  the  air? 

7.  Illustrate  the  fact  that  gases  will  mix,  whatever  their 
weight. 

8.  What  fact,  regarding  carbon  dioxide,  does  this  explain? 

9.  What  important  share  has  carbon  in  the  structure  of 
plants? 

10.  Describe  the  two  sets  of  cells  in  a  leaf. 

11.  What  happens  in  the  "leaf-green"  cells? 

12.  What  two  things  are  necessary  to  the  supply  of  leaf- 
green? 

13.  How  is  the  plant  dependent  upon  the  sun? 

14.  How  do  plants  which  have  no  leaf-green  secure  their 
food? 

15.  How  do  seeds  and  bulbs  grow  without  leaf-green? 

16.  Describe  the  breathing  of  plants  and  of  blossoms? 


CHAPTER   XIII 

CLIMATE 

The  plant's  whole  life  depends  as  we  have  seen,  upon 
the  sun,  for  without  sunlight  it  cannot  obtain  carbon  from 
the  air  and  must  starve.  And  this  is  equally  true  whether 
the  plant  manufactures  its  own  food  or  whether  it  feeds 
upon  what  has  been  manufactured  by  others.  The  para- 
site sucks  the  juices  of  plants  growing  in  the  light,  the 
fungus  feeds  upon  dead  vegetable  matter  which  has  grown 
in  the  light,  the  seedling  lives  at  first  upon  food  stored  in 
the  seed,  by  the  leaves  which  waved  in  the  sunlight,  and 
so  on. 

But  plants  require  of  the  sun  something  more  than 
light;  they  must  have  some  degree  of  heat  as  well — a 
very  small  degree  in  some  cases,  but  this  small  degree  is 
essential  to  bring  them  to  maturity.  Even  those  lowly 
plants  which  grow  in  snow  and  ice  cannot  dispense  with 
some  amount  of  heat,  and  though  they  contrive  to  exist  in 
the  lowest  temperatures,  they  remain  dormant  during  the 
winter,  and  only  wake  up  when  the  summer  sun  begins  to 
shine. 

Many  seeds  will  even  begin  to  grow  while  it  is  freezing, 
though  they  cannot  make  much  progress;  and  wheat  has 
been  known  to  germinate  when  actually  upon  ice,  and  to 
send  out  roots  into  it.  Barley  and  oats  will  also  send  out 
roots  with  the  thermometer  down  to  freezing  point,  but 
they  cannot  develop  seed-leaves  without  a  few  degrees  of 

149 


I50 


The  Great  World's  Farm 


warmth.  Maize,  as  might  be  expected,  requires  more 
heat  than  any  other  corn,  and  will  not  start  until  the  ther- 
mometer shows  about  fifteen  and  one-half  degrees  above 
freezing,  and  even  then  grows  but  slowly;  and  cucumber- 
seed  shows  no  sign  of  life  without  still  more  heat. 

But,  though  many  seeds  will  make  a  start  in  cold 
weather,  even  in  frost,  it  does  not  follow  that  they  will  do 
more  than  start;  for  a  plant  requires  different  degrees  of 
light  and  heat  at  different  times  in  its  life.  And  if  it  does 
not  receive  enough  at  the  important  period  when  it  has 
done  growing,  and  is  going  to  blossom,  the  chances  are 
that  it, will  bear  no  fruit.  For  fruit  cannot  do  much 
towards  feeding  itself,  and  though  it  does  take  up  carbon 
from  the  air,  it  is  chiefly  dependent  for  nourishment  upon 
the  leaves,  the  great  food  manufacturers.  But  in  a  cold 
summer,  the  leaves,  instead  of  passing  on  their  stock  of 
food  to  the  fruit,  and  themselves  turning  yellow,  as  they 
ought  to  do,  seem  to  be  quite  thrown  out  of  their  calcu- 
lations. They  keep  their  food  to  themselves,  and  remain 
green  and  juicy,  while  the  fruit  is  starved,  and  its  develop- 
ment checked.  In  very  bad  cases,  the  plant  puts  out  new 
shoots,  and  the  crop  never  comes  to  perfection;  for  the 
heat  which  is  quite  sufficient  for  the  growth  of  stems  and 
leaves  is  not  sufficient  for  the  growth  and  ripening  of  the 
fruit. 

If,  on  the  other  hand,  the  plant  gets  too  much  light 
and  heat  at  an  early  stage  in  its  life,  it  growls  up  and 
ripens  its  fruit  too  quickly,  before  it  is  properly  developed; 
and  this  is  what  takes  place  when  crops  are  sown  too  late 
in  the  year.  In  the  ordinary  course  of  nature,  seed 
generally  drops  and  sows  itself  as  soon  as  it  is  ripe,  and 
begins  to  grow  forthwith.      But  it  cannot  go  on  growing. 


Climate  151 

Winter  comes  and  checks  it,  and  it  is  obliged  to  put  off 
bearing  fruit  till  the  following  summer.  Plants  grown  in 
this,  the  natural  way,  are  generally  the  stronger,  if  they 
manage  to  survive  the  winter.  But  they  are  exposed  to 
more  perils  than  when  the  seed  is  sown  in  spring,  and  of 
course  they  are  much  longer  in  coming  to  perfection. 

Barley  sown  early  in  August  and  September,  as  soon 
as  it  is  ripe,  has  been  found  to  take  two  hundred,  and 
two  hundred  and  forty  days,  to  come  to  perfection,  which 
is  just  eight  times  as  long  as  it  often  does  in  Egypt,  where 
it  is  sown  and  ripened  not  only  the  same  year,  but  quite 
early  in  the  year. 

Provided,  however,  the  seed  be  not  sown  too  late,  the 
crop  seems  to  be  equally  good  whether  the  seed  be  sown 
in  autumn  or  spring.  Barley  sown  for  experiment  on  the 
2 1  St  of  April  came  to  perfection  in  eighty-eight  days, 
that  is,  by  the  i8th  of  July;  whereas  that  sown  five  weeks 
later  ripened,  indeed,  in  an  equal  number  of  days,  but 
prematurely,  before  the  grain  was  properly  developed, 
because  it  had  been  over-stimulated — too  much  hurried, 
in  fact,  during  the  long,  light,  warm  days  of  June. 

Of  all  the  influences  by  which  the  plant  is  surrounded, 
none  affect  it  so  powerfully,  for  good  or  evil,  as  light, 
temperature,  and  moisture,  or,  in  one  word,  climate. 
Where  the  climate  is  favorable,  the  quality  and  quantity 
of  the  soil  are  of  comparatively  little  im.portance,  for  the 
plant  manages,  to  make  the  very  utmost  of  what  it  has. 
But  where  the  climate  is  unfavorable,  no  soil,  however 
good  and  abundant,  can  make  up  for  it,  though  it  may  do 
something  to  lessen  the  evil  consequences. 

As  we  have  already  seen,  the  richest  soil  is  unable  to 
supply  the  place  of  water:   while  in  Guiana,  on  the  other 


152  The  Great  World's  Farm 

hand,  where  moisture  is  abundant,  and  the  chmate  genial, 
groups  of  trees  may  be  seen  growing  on  a  spur  of  the 
great  sandstone  mountains,  wherever  there  is  just  sand 
enough  to  afford  them  a  foothold.  The  sand  is,  of 
course,  not  mere  sand,  though  it  may  look  like  it;  but  the 
soil  is  undeniably  poor  and  shallow.  Yet,  helped  by  the 
climate,  the  trees  thrive,  as  they  could  not  possibly  do 
without  that  help. 

We  are  naturally  accustomed  to  look  upon  the  sun  as 
the  source  of  light  and  heat  to  our  planet;  but  tempera- 
ture does  not  depend  solely  upon  the  sun;  for  if  it  did, 
the  same  temperature  would  prevail  all  along  the  same 
parallel  of  latitude,  which  it  certainly  does  not. 

Rhine  grapes,  for  instance,  will  not  ripen  in  England; 
laurels  and  cameUias  flourish  all  the  year  round  on  the 
coast  of  Cornwall,  while  in  the  same  latitude  on  the  con- 
tinent, only  the  hardiest  trees  can  stand  the  winter.  The 
vine  can  hardly  flourish  at  the  mouth  of  the  Loire;  yet  it 
comes  to  perfection  in  Tokay,  which  lies  a  degree  further 
to  the  north;  and  Astrakhan,  in  nearly  the  same  latitude, 
has  summer  heat  enough  to  ripen  the  southern  fruits  of 
Italy,  and  even  of  the  Canary  Islands,  though  its  winters 
are  so  severe  that  no  vine-stock  would  be  able  to  live 
through  them  without  being  buried  several  feet  deep  in 
earth. 

It  is  evident,  therefore,  that  the  climate  of  a  country 
does  not  depend  solely  upon  its  position  with  regard  to  the 
equator.  Indeed,  the  great  characteristic  of  the  equatorial 
climate  is  not  so  much  its  heat  as  its  wonderful  uniform- 
ity. Hot  it  is,  of  course,  though  not  as  hot  as  the  plains 
of  north  India;  but  there  is  nothing  to  be  called  change 
of  season,  and  there  is  seldom  more  than  16'  or  17°  of 


Climate  i  r  o 

difference  between  day  and  night.  It  is  not  often  that 
the  thermometer  stands  above  90°  or  91°  F.  by  day,  or 
falls  below  74°  F.  by  night.  And  the  temperature  of  the 
soil  varies  but  little,  too.  Four  or  five  feet  below  the 
surface  it  never  varies  at  all,  and  remains  constantly  at 
80°  F.,  just  about  half-way  between  the  temperature  of 
night  and  day. 

Where  the  temperature  of  the  air  varies  more,  there 
the  temperature  of  the  soil  varies  more  also,  and  to  a 
greater  depth.  At  the  equator,  the  sun  affects  only  the 
upper  four  or  five  feet  of  the  soil,  the  change  between  day 
and  night  being  unfelt  below  this;  but  in  England,  the 
change  between  summer  and  winter  is  felt  to  a  depth  of 
fifty  or  sixty  feet,  probably;  and  below  this  the  temperature 
remains  steady  at  but  a  little  above  40°  F.,  which  is  about 
the  mean  temperature  of  the  air  in  England,  as  80°  F.  is 
that  of  the  equatorial  region — half-way  between  the  two 
extreme  points  to  which  the  thermometer  rises  and  falls. 

But  this  fact,  that  the  depth  at  which  the  temperature 
of  the  soil  remains  always  the  same  is  so  much  greater  in 
one  case  than  in  the  other,  has  much  influence  upon  the 
two  climates;  and  for  this  reason:  whenever  a  hot  body 
is  in  contact  with  a  cold,  or  cooler  one,  it  at  once  gives 
up  some  of  its  heat  to  this  other,  and  continues  to  do  so 
until  there  is  no  difference  between  the  two. 

When,  therefore,  the  sun  warms  the  surface  of  the 
soil,  the  upper  layer  parts  with  some  of  its  heat  to  the  one 
below  it,  this  to  the  next  below,  and  so  on,  until  that  depth 
is  reached  where  the  temperature  is  always  the  same.  At 
the  equator,  therefore,  the  heat,  having  only  four  or  five 
feet  of  soil  to  travel  through,  soon  raises  the  temperature 
of  the  whole  mass  equally,  and  then,  as  it  cannot  descend 


154 


The  Great  World's  Farm 


any  lower,  it  goes  on  adding  to  the  heat  of  these  upper 
layers,  in  which  it  accumulates.  At  night,  when  the  sun 
is  gone,  the  surface  of  the  soil  cools,  and  the  reverse  pro- 
cess begins;  the  heat  stored  during  the  day  gradually 
passes  up  again  to  the  surface,  and  from  the  surface  into 
the  air,  so  that  both  earth  and  air  are  kept  at  a  more  even 
temperature  than  would  otherwise  be  the  case. 

But  where,  as  in  England,  the  sun  has  forty  or  fifty 
feet  of  cool  earth  to  warm,  naturally  it  is  much  longer 
about  it,  and  the  whole  mass  is  consequently  not  warmed 
equally  through  till  summer  is  at  its  height.  Then,  and 
not  till  then,  the  whole  mass  being  warm,  heat  begins  to 
be  stored  during  the  day  in  the  upper  layers,  and  is  given 
up  again,  when  the  sun  is  down,  to  warm  the  air  at  night. 
Hence  we  have  warm  nights  in  July  and  August;  and 
winter  is  less  cold  than  it  would  otherwise  be,  thanks 
to  the  heat  gradually  given  back  by  the  great  mass  of 
earth. 

But  the  heat  given  back  to  the  air  in  this  way  would 
quickly  escape,  and  benefit  us  little,  were  it  not  for  the 
moisture  in  the  air,  which  acts  the  part  of  a  blanket,  and 
keeps  it  near  the  earth.  At  the  equator,  the  air  is  gen- 
erally in  a  very  moist  condition  all  the  year  round;  and  this 
moisture,  while  serving  the  part  of  a  blanket  by  night, 
acts  as  a  veil  or  parasol  by  day,  and  prevents  the  sun's 
rays  from  being  too  scorching. 

It  is  to  the  large  quantity  of  moisture  in  the  air  that 
the  region  of  the  equator  owes  its  very  even  temperature, 
therefore. 

In  the  dry  plains  of  north  India  the  heat  is  scorching, 
much  greater  than  at  the  equator,  just  for  want  of  this 
veil ;   and  the  nights  are  often  so  cold  that  water  is  frozen, 


Climate  i^^ 

because  the  heat  received  by  day  all  escapes  again  through 
the  clear  air. 

Everybody  knows  that  a  clear  night  is  a  cold  night, 
while  a  misty  or  cloudy  one  is  comparatively  warm. 

Among  other  circumstances,  therefore,  which  greatly 
affect  the  climate  of  a  country  is  its  nearness  to,  or  dis- 
tance from,  the  ocean.  For  where  constant  evaporation 
is  going  on,  on  a  large  scale,  as,  of  course,  it  is  from  the 
ocean,  there  the  air  must  needs  be  loaded  with  moisture, 
with  the  consequences  already  mentioned:  the  nights  are 
warmer,  the  days  cooler,  the  winters  less  severe,  the  sum- 
mers less  scorching.  In  one  word,  the  climate  is  more 
equable.  Moreover,  the  ocean  is  warmer  than  the  land, 
in  winter  and  by  night,  while  it  is  cooler  in  summer  and 
by  day;  and  this  tends  to  further  equalize  the  tempera- 
ture. 

If  the  neighborhood  of  the  ocean  tends  to  equalize 
climate,  the  neighborhood  of  any  large  expanse  of  dry  soil 
does  exactly  the  reverse,  inasmuch  as  it  dries  the  air. 

If  the  Sahara  were  covered  with  water,  the  climate  of 
the  south  of  Europe  would  be  many  degrees  less  warm 
than  it  is;  for  the  wind  passing  over  it  would  be  cooled 
instead  of  heated  as  it  now  is.  It  would  also  be  moistened, 
and  so  more  snow  would  fall  in  the  Alps,  and  less  would 
melt  in  the  summer. 

Then,  again,  there  are  the  many  ocean  currents,  hot 
and  cold,  which  also  influence  climate  to  a  considerable 
extent.  Western  Europe  would  be  far  colder  than  it  is 
without  the  gulf  stream,  which  brings  about  one  hundred 
and  sixty-six  thousand  cubic  miles  of  hot  water  from  the 
tropics  to  the  North  Atlantic  in  the  course  of  each  year. 
And  this  tremendous  volume  of  steaming  water,  besides 


156  The  Great  World's  Farm 

warming  the  air,  loads  it  with  moisture;  so  that  it  is  easy 
to  understand  why  the  winter  climate  of  Ireland  should  be 
mild  enough  to  allow  of  myrtles  flourishing  out  of  doors, 
and  yet  why  the  summer  heat  should  not  be  sufficient  to 
ripen  certain  fruits,  owing  to  the  thick  veil  of  vapor  which 
screens  it  from  the  sun. 

Other  local  circumstances  which  affect  climate  in  a 
greater  or  less  degree  are  the  presence  of  forests,  rivers, 
lakes,  mountains,  which  cannot  now  be  dealt  with  in 
detail. 

But  plants  are  also  affected  in  a  minor  degree  by  the 
color  of  the  soils  in  which  they  grow. 

Dark  substances  absorb  more  heat  than  light  ones  do; 
and  snow  will  melt  more  quickly  if  a  piece  of  black  cloth 
be  stretched  above  it,  even  though  the  two  do  not  touch 
one  another.  In  the  Arctic  regions  the  ice  melts  much 
faster  wherever  a  small,  dark  brown  plant,  of  the  same 
family  as  the  red  snow,  grows,  because  it  attracts  the 
heat.  So,  too,  in  some  parts  of  Switzerland  the  peasants 
hasten  the  departure  of  the  snow  by  strewing  it  with  black 
powdered  slate. 

Dark  soils  are,  therefore,  usually  warmer  than  light 
ones;  and  it  is  not  an  uncommon  thing  for  gardeners  to 
sprinkle  a  light  colored  soil  with  peat,  charcoal,  or  vege- 
table mold  to  warm  it,  for  these  all  act  as  sun-traps. 

Melons  are  thus  ripened,  even  in  the  coolest  summers, 
at  Freiberg,  in  Saxony,  by  means  of  a  layer  of  coal-dust. 

Grapes,  too,  in  the  Rhine  district,  ripen  best  where  the 
ground  is  covered  with  fragments  of  black  slate;  and  the 
vines  are  purposely  kept  near  the  ground,  that  they  may 
have  the  full  benefit  of  the  heat  which  the  slate  absorbs  by 
day  and  gives  up  again  by  night. 


Climate 


157 


The  difference  in  temperature  between  two  substances, 
one  of  which  is  white  and  the  other  black,  when  both  are 
equally  exposed  to  the  sun,  is  very  remarkable.  There 
will  be  as  much  as  thirteen  or  fourteen  degrees  difference, 
for  instance,  in  the  temperatures  of  a  piece  of  lamp-black 
and  of  a  piece  of  magnesia. 

But  though  color  makes  such  an  important  difference 
in  the  power  to  absorb  heat,  it  has  no  influence,  appar- 
ently, upon  the  power  to  retain  it.  Indeed,  though  sand 
may  absorb  heat  less  quickly  than  a  darker  soil  does,  when 
once  it  is  warm  it  remains  warm  longer  than  any  other. 
The  coarser  it  is,  too,  the  less  quickly  it  cools;  and  as 
coarse  gravel,  once  thoroughly  heated,  retains  some  degree 
of  heat  even  through  the  night,  it  is  found  useful  to  put  it 
round  grape-vines  to  keep  them  warm. 

Great,  and  especially  sudden,  changes  of  temperature 
are  particularly  trying  to  most  plants,  though  such  as  grow 
in  deserts  have  become  so  accustomed  to  being  scorched 
by  day  and  frozen  by  night,  as  at  least  to  manage  to  keep 
ahve.  But  though  an  even  temperature  is  in  some  ways 
most  desirable,  it  does  not  by  any  means  follow  that  all 
plants  would  thrive  in  the  equatorial  region.  That  region, 
as  has  been  said,  is  characterized  less  by  its  great  heat 
than  by  its  remarkable  uniformity  of  climate.  It  knows 
no  change  of  seasons :  it  is  always  summer,  always  spring, 
and  always  autumn  there,  and  many  trees  bear  both  flow- 
ers and  fruit  at  the  same  time.  But  this  constant  activity, 
though  it  suits  the  trees  and  plants  accustomed  to  it,  is  too 
much  for  our  European  fruit-trees  and  other  plants;  for 
these  are  in  the  habit  of  taking  a  winter  sleep,  and  canno: 
get  on  without  it.  Transported  to  the  equatorial  region, 
they  grow,  indeed,  freely  enough,  but  too  freely;  for  they 


158  The  Great  World's  Farm 

become  evergreen,  putting  out  fresh  leaves  all  the  year 
round,  and  are  so  exhausted  for  want  of  their  customary 
rest  that  they  are  unable  to  ripen  their  fruit.  This  is  the 
case  even  when  they  are  taken  to  the  cooler  hill-country 
of  Ceylon;  and  it  is  true  even  with  regard  to  the  vine, 
which,  though  a  native  of  warm  climates,  still  is  not  a 
tropical  plant,  and  is  accustomed  to  shed  its  leaves  year 
by  year.  In  the  tropics,  however,  its  leaves  remain  green, 
instead  of  giving  up  their  stores  to  feed  the  fruit  as  they 
ought;  the  grapes  fall  off  almost  unformed,  and  the  vine 
puts  all  its  energy  into  growing  leaves  instead  of  fruit,  not 
having  strength  for  both.  The  one  thing  which  it  lacks  is 
i-est — the  rest  which  in  winter  it  is  compelled  to  take. 

It  being,  however,  impossible  to  provide  the  vines  with 
winter-cold  in  Ceylon,  it  was  suggested  that  heat  might 
perhaps  be  made  to  answer  the  purpose  as  well,  and  the 
experiment  was  tried  of  laying  the  roots  bare  for  a  time  to 
the  strongest  sun.  This  had  the  effect  of  checking  the 
flow  of  sap  as  effectually  as  frost  could  have  done:  the 
leaves  dropped,  the  vines  had  their  sleep,  and  awoke  from 
it  so  refreshed  and  invigorated  that  they  were  able  to  bring 
their  crop  to  maturity;  and  this  plan  has  been  adopted 
with  success  both  in  Ceylon  and  Bombay. 

In  those  tropical  regions,  outside  the  equatorial  belt, 
where  there  are  periodical  rainy  seasons  and  long  droughts, 
the  latter  answer  all  the  purpose  of  winter,  and  are,  indeed, 
winter,  so  far  as  vegetation  is  concerned,  in  spite  of  their 
intense  heat.  Trees  and  shrubs  are  as  leafless  in  the  desert 
of  Nubia,  for  instance,  before  the  rains  set  in,  as  if  it  were 
mid-winter,  in  spite  of,  or,  rather,  in  consequence  of,  the 
terrible  heat;   and  thus  a  time  of  rest  is  secured  to  them. 

In  the  Far  North  we  have  a  very  different  state  of  things. 


Climate  irn 

Here,  instead  of  its  being  necessary  to  secure  that  the 
plants  shall  have  rest,  the  great  thing  is  to  provide  that 
they  shall  make  the  utmost  of  the  very  short  spring  and 
summer  which  are  all  that  fall  to  their  lot.  Their  time  of 
sleep  lasts  on  an  average  ten  months,  and  during  the 
remaining  two  months  they  have  everything  to  do,  so  that 
it  is  most  necessary  that  they  should  make  the  most  of 
their  time.  The  days  are,  of  course,  very  long,  which  is 
a  help,  while  the  nights  are  so  light  as  to  be  hardly  like 
night;  and  if  Professor  Nordenskj old's  observations  be 
trustworthy,  it  seems  that  the  plants  do  indeed  turn  every 
moment  to  account,  by  growing  all  night  as  well  as  all  da  v. 

But  many  of  them  do  a  great  deal  of  growing  in 
advance,  so  that  as  soon  as  the  summer  comes  their  blos- 
soms and  fruit,  which  need  heat  more  than  the  leaves, 
may  be  ready  at  once  to  take  advantage  of  it.  These 
plants,  that  is  to  say,  make  very  large,  strong  buds,  which 
are  packed  full  of  leaves  and  blossoms,  in  a  more  or  less 
undeveloped  state,  but  with  all  their  parts  ready,  before 
the  winter  sets  in.  Directly  the  growing  time  comes  round 
again,  therefore,  they  can  burst  out,  and  begin  to  gather 
food  from  the  air  at  once,  and  the  plant  is  able  to  blossom 
very  early,  thus  insuring  as  much  time  as  possible  for  the 
perfecting  of  the  fruit. 

Most  of  the  plants  ripen  their  fruit,  but  some  few  are 
not  able  to  do  so,  except  now  and  then,  when  the  summer 
is  hotter  or  longer  than  usual;  and  some  which  are  annu- 
als further  south  become  perennials  here,  as  they  would 
not  have  time  to  grow  from  seed,  and  ripen  seed,  in  one 
short  season. 

During  the  long  winter  many  are  of  course  protected 
by  the  snow;  but  there  are  wide  surfaces  here  and  there 


t6o  The  Great  World's  Farm 

left  quite  bare  of  covering,  and  yet  even  here  plants  man- 
age to  survive,  some  without  any  protection  whatever, 
others  because  they  are  buried  under  a  deep  layer  of  dead 
leaves  and  stems.  Whether  in  ** deserts"  of  ice  or  ''des- 
erts" of  sand,  it  would  be  equally  difficult  to  find  any 
spaces  of  large  extent  where  vegetable  life  of  some  kind 
or  other  does  not  exist,  at  least  during  certain  seasons  of 
the  year. 

QUESTIONS  FOR  REVIEW 

1.  How  important  is  climate  in  the  life  of  a  plant? 

2.  How  do  conditions  vary  in  the  same  latitude? 

3.  What  is  the  great  characteristic  of  the  climate  of  the 
equator. 

4.  Show  how  the  temperature  of  air  and  soil   affect  each 
other  in  different  latitudes. 

5.  What  effect  has  the  presence  or  absence  of  moisture? 
Illustrate. 

6.  What  influence  has  the  gulf  stream? 

7.  Why  are  plants  affected  by  the  color  of  the  soils  in  which 
they  grow?     Illustrate. 

8.  How  do  soils  differ  in  the  way  in  which  they  retain  heat? 

9.  Why  is  the   equatorial  climate  not  best  for  all  plants? 
Illustrate. 

10.  Compare  the  conditions  of  plants  in  Nubia  and  in  the 
Far  North. 


CHAPTER    XIV 

BLOSSOM  AND  SEED 

Plants,  even  the  very  humblest  and  lowliest,  have,  as 
we  have  seen,  many  requirements  in  the  way  of  food  of 
various  kinds,  water,  air,  light,  and  warmth.  But  having 
seen  them  duly  provided  with  all  these,  we  might  fancy 
that  now  at  last  all  their  wants  were  satisfied,  and  that 
nothing  more  remained  but  for  them  to  make  the  best  of 
their  opportunities  and — grow. 

But  all  depends  upon  what  we  consider  to  be  the  plant's 
object  in  life.  For  instance,  we  may  be  quite  satisfied  to 
grow  orange-trees  for  their  blossom  merely,  or  maize  for 
use  as  forage,  and  palms  for  the  sake  of  their  fohage,  in 
climates  where  it  is  impossible  for  any  one  of  them  to 
ripen  their  fruit.  And  provided  they  throve  and  answered 
these  purposes,  our  object  would  be  attained. 

But  plants  in  the  natural  state  grow  to  bear  and  ripen 
fruit.  All  the  rest  of  their  lives  is  merely  a  preparation 
for  this  one  grand  end.  The  roots  draw  food  from  the 
soil,  and  the  leaves  do  the  same  from  the  air,  all  for  the 
purpose  of  feeding  and  maturing  the  fruit — the  one  aim  to 
which  everything  tends. 

Of  course,  where  man  comes  upon  the  scene  it  is  quite 
another  matter,  as  he  can  take  cuttings  of  some,  divide 
the  roots  of  others,  and  fetch  continual  supplies  of  seed 
from  the  ends  of  the  earth,  if  necessary.  But  the  wild 
plant  has  not  these  resources  to  fall  back  upon,  and  if  its 

i6i 


1 62  The  Great  World's  Farm 

race  is  to  continue,  it  must  as  a  rule  be  able  to  perfect  its 
seed,  otherwise  it  will  merely  thrive  for  a  time,  longer  or 
shorter,  according  as  it  is  an  annual  or  a  perennial,  and 
then  it  will  perish  without  descendants. 

But  in  very  many  cases  the  plant,  like  Mr.  Belt's  scar- 
let-runners already  mentioned,  is  quite  unable  to  perfect 
seed  without  the  help  of  what  we  may  call  nature's  under- 
gardeners.  The  plant  does  much  for  its  offspring;  it  col- 
lects and  stores  food,  it  drains  itself  of  its  own  life-juices 
for  their  benefit,  but  it  cannot  always  do  everything;  and 
if  these  under-gardeners  were  banished  from  the  earth, 
some  plants  would  speedily  vanish  also. 

Both  blossoming  and  fruit-bearing  are  processes  more 
or  less  exhausting  to  the  plant,  for  neither  flowers  nor 
fruits  do  much,  though  they  do  something,  towards  feed- 
ing themselves.  Annuals  blossom  and  bear  fruit  once  and 
then  die  entirely,  roots  and  all,  their  leaves  and  stems 
being  drained  of  nourishment  by  the  end  of  the  season. 
Others,  perennials,  die  down,  but  their  roots  remain  alive; 
and  others  again,  merely  shed  their  exhausted  leaves,  and 
grow  fresh  ones,  for  several  or  many  seasons  in  succes- 
sion. Others  again,  take  more  than  one  season  to  store 
food  before  they  venture  upon  the  expense  of  having  blos- 
soms at  all;  and  others  take  many  years  to  prepare  for 
this  great  effort,  and  when  it  is  at  last  accomplished,  the 
great  end  of  their  lives,  they  die  of  mere  exhaustion. 

The  food  of  blossom  and  fruit  is,  as  has  been  said, 
very  generally  accumulated  in  the  leaves  and  stems  of  the 
plant;  but  sometimes  the  root  serves  as  the  main  store- 
house. The  turnip,  for  instance,  like  other  biennials, 
spends  the  first  year  of  its  life  in  doing  nothing  but  gather 
a  store  of  food  by  means  of  its  roots  and  its  tuft  of  leaves. 


Blossom  and  Seed  163 

It  does  not  shoot  up,  and  it  makes  no  attempt  to  blossom; 
and  as  the  farmer  does  not  want  turnip-blossom,  and  does 
want  roots,  he  takes  the  latter  while  they  are  plump,  and 
well  filled  with  the  food  intended  for  the  seed.  If  he 
waited  till  the  next  year  he  would  see  his  turnip-plants 
shoot  up  rapidly  and  blossom;  and  very  thriving  they 
would  look,  no  doubt;  but  all  this  time  they  would  be 
sucking  away  at  the  roots,  which  would  be  losing  their 
plumpness,  and  growing  gradually  hollower  and  more  hol- 
low, until,  by  the  end  of  the  second  year,  they  would  be 
reduced  to  nothing  but  fiber,  and  be  quite  useless. 

We  have  spoken  already  of  bulbous  plants,  such  as 
crocuses,  whose  blossoms  are  nourished  on  the  food  pre- 
viously stored  for  them  in  the  bulb,  by  the  leaves,  which, 
in  most  cases,  do  the  chief  part  of  their  work  after  the 
blossoms  have  faded.  But  in  some  instances,  as  in  that 
of  the  colchicum,  or  meadow  saffron,  they  come  up  and 
make  their  preparations  in  the  spring,  for  the  blossoms 
which  do  not  appear  till  the  autumn,  long  after  the  leaves 
have  vanished.  In  these  cases  the  food  for  the  blossoms 
is  stored  in  the  bulbs;  and  if  a  tidy  gardener  unwarily  cuts 
off  the  leaves  before  the  bulb  is  properly  stocked,  he 
starves  the  blossoms. 

But  some  plants  take  years  to  prepare  food  sufficient 
for  the  supreme  effort  of  their  lives. 

The  American  aloe,  for  instance,  which  was  sup- 
posed to  blossom  only  once  in  a  hundred  years,  though  it 
does  not  wait  quite  so  long  as  this,  does  actually  wait  five 
or  six  years  in  its  own  country,  and  from  fifty  to  seventy 
in  ours,  before  it  attempts  to  send  up  a  flower-spike.  But 
when  it  does  begin,  it  grows  with  such  tremendous 
energy — at  the  rate  of  a  foot  a  day  even  in  our  conser- 


164  The  Great  World's  Farm 

vatories — that  one  can  well  understand  its  need  of  a  large 
store  of  food  ready  for  immediate  use,  since  it  would  be 
impossible  for  leaves  and  roots  to  collect,  manufacture, 
and  supply  it  as  fast  as  it  is  wanted. 

The  aloe  does  not,  however,  always  die  of  its  effort, 
and  may  live  to  blossom  again,  some  years  later;  but  the 
Talipot  palm,  though  it  attains  a  great  age,  spends  its 
whole  life  in  accumulating  food  for  its  progeny;  and  hav- 
ing once  blossomed,  it  is  quite  exhausted,  and  perishes. 

Blossoming,  then,  is  a  serious  matter  for  all  plants,  and 
not  to  be  undertaken  without  due  preparation.  But  it  is 
a  curious  fact  that  the  size  of  a  plant's  blossoms  is  often 
quite  independent  of  the  size  of  the  plant  itself.  Many  a 
forest-tree,  for  instance,  bears  flowers  which  are  quite 
minute  and  insignificant;  others,  as  some  of  the  palms, 
bear  spikes  of  blossom  several  feet  in  length  and  leaves  in 
proportion.  As  a  rule,  however,  trees  have  small  leaves, 
small,  dull  blossoms,  and  small  seeds  for  their  size;  but 
they  bear  all  three  in  large  numbers.  A  diminutive  cac- 
tus, only  a  few  inches  high,  on  the  other  hand,  may  boast 
a  glorious  crimson  flower,  measuring  two  or  three  inches 
across;  but  then  it  has  to  be  satisfied  with  one,  or  per- 
haps two.  The  beautiful  night-flowering  cactus  attains 
some  size,  but  it  is  a  conservatory  plant,  not  a  tree,  yet 
its  blossoms  measure  half  a  foot  across  and  it  bears  at 
times  as  many  as  twenty  or  thirty  together. 

The  largest  known  blossom,  however,  is  that  of  the 
extraordinary  Rafflesia  Arnoldi,  a  native  of  Java  and 
Sumatra,  which,  much  more  truly  than  even  the  orchids, 
is  **all  blossom,"  for  it  has  neither  branches,  leaves,  nor 
roots.  Of  course,  therefore,  it  must  needs  be  a  parasite, 
living  by  and  sucking  the  life-juices  from  others;   and  it 


Blossom  and  Seed  165 

produces  a  huge  blossom,  more  than  a  yard  across,  mainly 
at  the  expense  of  the  vine-like  plant  upon  which  it  fixes  itself. 

It  is  not  by  any  means  a  beautiful  object,  and  its  petals, 
which  are  thick  and  fleshy  in  texture  as  well  as  flesh-col- 
ored, have  the  smell  of  tainted  beef.  This  monster  takes 
several  months  to  come  to  perfection,  and  then  weighs 
about  fifteen  pounds;  after  which  it  begins,  in  a  few 
days,  to  wither  away. 

An  ordinary,  complete,  simple  blossom,  whether  large 
or  small,  brightly  colored  or  inconspicuous,  consists  of 
two  sets  of  parts,  or  organ,  an  outer  and  an  inner  set.  It 
is  the  function  of  the  inner  set  to  form  the  seed;  and  it  is 
the  function  of  the  outer  set  to  protect  the  inner  from  all 
injury,  and  also,  in  many  cases,  to  attract  the  under-gar- 
deners  already  referred  to,  whose  good  oflices  are  required 
for  the  development  of  the  seed. 

The  perfecting  of  the  seed  is  the  great  thing  to  be 
accomplished;  and  those  parts  of  the  blossom  which  con- 
tribute to  this  object  are  placed  in  the  center,  as  far  out 
of  harm's  way  as  possible.  If  we  examine,  for  instance, 
a  common  primrose,  splitting  it  carefully  upwards  from 
the  base  of  the  flower,  we  shall  see  in  the  very  center  a 
hair-like  stalk,  with  a  knob  at  the  upper  end  and  a  hollow 
swelling  at  the  lower  end.  On  splitting  open  this  hollow 
part,  we  find  that  it  contains  a  number  of  very  minute 
grains,  ovules,  or  little  eggs,  which,  in  the  ordinary  course 
of  things,  would  be  converted  into  seeds. 

This  central  organ  is  the  pistil,  which  consists  of  one 
or  more  bodies,  named  carpels,  each  with  its  hollow  case, 
or  ovary,  below,  and  its  stalk,  or  style,  above;  and  these 
are  either  distinct  one  from  another,  or  combined  into  one 
organ. 


1 66  The  Great  World's  Farm 

Outside  the  pistil  stand  the  dust-spikes,  or  stamens — 
stalks  bearing  each  a  double  sac,  or  anther,  which  is  filled 
with  the  dust  known  as  pollen.  Pistil  and  stamens  together 
form  the  inner  and  more  important  set  of  organs. 

The  outer  set  consists  of  a  double  envelope  of  leaves; 
the  inner,  or  petals,  more  delicate  in  texture  and  more 
varied  in  color,  forming  the  corolla;  and  the  outer,  or 
sepals,  generally  green,  and  forming  the  calyx.  A  per- 
fect flower  has  all  these  parts,  and  some  have  double  rows 
of  each.  Naturally  our  eye  is  attracted  chiefly  by  the 
brightly  colored  part  of  a  blossom,  and  we  think  little 
about  the  inner  organs,  which  are  often  almost  or  quite 
hidden  from  our  sight.  But  it  is  these  inner  organs 
which  are  really  the  only  absolutely  necessary  parts  of  a 
blossom. 

Many  flowers  have  no  calyx  at  all;  some  have  no 
petals;  but,  provided  they  have  stamens  and  pistil,  they 
can  still  accomplish  all  that  is  necessary  for  the  perfecting 
of  their  seed.  Even  pistil  and  stamens,  however,  may 
be,  and  often  are,  reduced  in  size  and  deprived  of  their 
stalks;  but  dust-cells  there  must  be,  and  ovules,  or  grains 
to  be  developed  into  seeds,  there  must  be  if  the  plant  is 
to  bear  seed  at  all. 

Now  all  these  organs,  the  inner  set  as  well  as  the  outer 
set,  are  really  leaves — leaves  whose  appearance  and  duties 
in  life  have  been  altered.  The  calyx  still  looks  more  or 
less  leaf-like  usually,  and  it  is  not  difficult  to  believe  that 
the  petals  might  be  leaves,  too,  though  more  delicate  and 
more  daintily  colored.  But  it  is  less  easy  to  believe  the 
same  of  stamens  and  pistil.  Let  us,  however,  look  for 
them  in  any  double  blossom,  and  we  shall  find  few  if  any, 
for  they  have  been  changed  into  petals.     It  is  blossoms 


I 


Blossom  and  Seed  167 

with  many  stamens,  such  as  the  rose,  ranunculus,  anem- 
one, or  blossom  with  many  florets,  such  as  the  daisy 
and  dahlia,  which  are  most  commonly  doubled  by  culti- 
vation. 

Nature  does  not  ^tow  many  double  flowers,  for  wild 
plants  need  seed,  and  double  flowers  produce  little  if  any, 
seed  being  sacrificed  to  petals.  Geraniums,  which  have 
only  ten  stamens,  are  among  the  plants,  however,  which 
have  a  tendency  to  increase  the  number  of  their  petals; 
and  among  the  single  blossoms,  one  may  often  be  seen 
with  a  petal  or  two  more  than  the  rest,  or  an  extra  small 
petal,  which  is  half-way  between  a  petal  and  a  stamen. 
If  the  seed  from  this  blossom  were  saved,  some  of  the 
next  generation  of  plants  might  have  still  more  petals  and 
still  fewer  stamens,  and  by  carefully  cultivating  those 
having  these  peculiarities  the  gardener  would  at  last 
obtain  quite  double  blossoms.  The  orange  day-lily,  too, 
may  sometimes  be  seen  with  one  or  more  stamens  enlarged 
into  small  petals  and  bearing  an  imperfect  anther. 

But  we  have  now  to  see  what  it  is  which  changes  the 
little,  immature  grains  in  the  hollow  part  of  the  pistil  into 
seeds,  capable  of  growing  into  independent  plants.  At 
first  they  are  mere  specks  of  matter  to  all  appearance,  and 
so  they  will  remain  unless  they  are  brought  into  close  con- 
tact with  some  of  the  dust  contained  in  the  sacs  borne  by 
the  stamens.  This  is  the  special  stimulant  which  they 
need  to  make  them  develop,  and  if  it  be  kept  from  them 
they  will  simply  shrivel  and  die,  for  nothing  else  will  do 
instead. 

This  dust,  or  pollen,  is  contained  in  the  anther,  which 
is  usually  seated,  or  more  often  perched,  and  apparently 
very  loosely  perched,  too,  on  the  end  of  a  stalk. 


1 68  The  Great  World's  Farm 

When  the  pollen  is  ripe,  that  is,  ready  for  the  use  of 
the  grains  contained  in  the  pistil,  the  chambers  open  and 
it  is  discharged.  The  pollen  consists  of  hollow  grains, 
varying  very  much  in  size  and  shape  in  different  plants, 
though  always  alike  in  the  same  plant. 

Pollen-grains  are  very  beautiful  objects  v/hen  seen 
through  the  microscope,  though  they  look  like  nothing  but 
powdery  dust  to  the  naked  eye.  Their  color  is  usually 
yellow  or  brown,  but  they  are  also  red,  green,  blue,  whit- 
ish, and  even  black;  and  though  their  general  shape  is 
round,  or  egg-shaped,  they  are  of  many  other  forms, 
wonderful  in  their  great  beauty  and  variety,  and  reminding 
one  of  microscopic  shells. 

Some  pollen-grains,  for  instance,  are  covered  with 
ridges  or  grooves;  others,  such  as  those  of  the  hollyhock 
and  aster,  with  spines;  others  again  with  hairs  or  thorns; 
those  of  the  thistle  are  many-sided;  of  the  fuchsia  and 
evening  primrose,  triangular;  of  the  chicory,  six-sided; 
and  if  we  could  see,  we  should  no  doubt  find  a  reason 
for  every  change  of  form  and  color,  and  discover  that  each 
was  exactly  adapted  for  its  own  special  purpose. 

Every  pollen-grain  is  delicately  coated  with  oil,  prob- 
ably as  a  protection  against  damp  and  wet,  and  all  have 
upon  them  markings,  like  pores  or  slits,  to  some  of  which 
there  are  lid-like  covers.  Usually  each  grain  consists  of 
a  single  cell,  though  sometimes  there  are  more,  and  the 
cells  are  filled  with  a  liquid  of  a  most  nutritious  kind,  con- 
sisting partly  of  starch,  partly  of  oil,  and  partly  of  some 
jelly-like  nitrogenous  compound. 

It  is  pollen  which  is  the  flesh-forming  food  of  the  bee. 
It  may  live  on  honey,  which  is  mainly  sugar — not  nitroge- 
nous— during  the  winter,  when  it  is  doing  no  work,  but 


Blossom  and  Seed  169 

when  it  is  taking  long  journeys  to  and  fro,  it  needs  some- 
thing more  nutritious  to  make  up  for  the  waste  occasioned 
by  so  much  muscular  exercise,  and  it  eats  pollen,  besides 
carrying  it  home  to  make  bee-bread  for  the  young  grubs. 

But  our  concern  now  is  with  the  ovules,  the  possible 
seeds,  lying  inclosed  in  the  ovary  at  the  base  of  the  pistil, 
while  the  pollen,  which  is  to  make  seeds  of  them,  is  in  the 
anther-sacs  above,  and  as  it  would  seem,  out  of  and 
beyond  their  reach.  The  question  is,  how  are  the  two  to 
be  brought  together? 

In  describing  the  primrose,  we  mentioned  that  the  top 
of  the  pistil  ends  in  a  knob;  and  this  knob  is  a  matter  of 
great  importance.  It  is  called  the  stigma,  and  is  of  all 
sorts  of  different  shapes  in  different  flowers;  sometimes 
merely  a  point,  sometimes  large  and  divided  into  lobes, 
sometimes  feathery,  as  in  most  of  the  grasses;  but  what- 
ever its  shape,  it  has  no  covering  of  outer  skin,  as  the 
stalk  on  which  it  is  borne  has,  and  it  is  more  or  less 
sticky,  and  often  crowned  with  a  bead  of  nectar.  This 
bead  is  so  large  in  some  plants — as,  for  instance,  the  white 
lily — that  it  may  be  taken  oft';  and  if  then  a  few  grains  of 
pollen  from  the  anther  be  sprinkled  upon  it,  we  shall  see 
that  these  will  in  about  half  an  hour  begni  to  swell  and 
grow.  Each  grain  will  put  forth  a  slender  tube,  very  mi- 
nute, of  course;  but  in  an  hour  or  two  it  will  have  length- 
ened out,  and  the  fluid  contained  in  the  pollen-grain  may 
be  seen  passing  down  one  side  of  the  tube  and  up  the 
other.  Pollen-grains  may  also  be  grown  in  a  solution  of 
gum  or  sugar. 

Now  this  is  exactly  what  takes  place  when  pollen  falls 
upon  the  sticky  stigma  at  the  tip  of  the  pistil,  only  that 
instead  of  growing  in  an  objectless  way,  each  grain  sends 


lyo 


The  Great  World's  Farm 


out  its  tube,  or  sometimes  several  tubes,  in  the  most  busi- 
ness-like manner,  and  with  the  most  precise  and  definite 
aim.  The  object  is  to  reach  one  of  the  ovules  below,  and 
to  do  this  the  tube,  in  many  cases  of  more  than  hair-like 
fineness,  pierces  its  way  downwards  through  the  stalk  of 
the  pistil,  and  makes  straight  for  its  aim  with  unerring- 
exactness,  entering  one  of  the  ovules  by  an  opening  in  it 
which  exists  for  this  purpose. 

Sometimes  the  tube  may  take  months  to  reach  the 
ovule,  but  more  usually  it  accomplishes  its  purpose  in  a 
few  days  or  hours.  As  soon  as  it  has  made  its  way  into 
the  ovule,  it  begins  to  pass  into  it  the  fluid  contents  of  the 
pollen-grain,  and  the  ovule  begins  to  grow. 

But  the  ovule  does  more  than  grow,  it  acquires  a  new 
character.  At  first  it  was  a  mere  speck  of  matter,  con- 
taining a  germ-cell,  indeed,  but  no  germ,  no  rudimentary 
or  embryo  plantlet,  such  as  one  may  see  on  splitting  open 
a  bean,  pea,  nut,  or  any  other  seed  large  enough  for  the 
purpose.  The  tube  sent  out  by  the  pollen-grain  enters 
the  ovule,  and  the  germ  is  developed  and  vivified  by  the 
liquid  which  passes  down  it.  The  seed,  which  before  was 
unfertile,  and  could  never  have  germinated  and  produced 
a  plant,  is  now  fertilized,  made  fruitful,  and  if  allowed  to 
come  to  maturity  it  will  be  capable  of  producing  a  plant 
like  that  by  which  it  is  borne. 

It  is  quite  possible  in  certain  cases  for  ovules  to  grow 
and  even  to  attain  the  size  of  seeds  without  being  seeds, 
without  having  within  them  any  living  germ  capable  of 
independent  hfe  and  growth.  For  each  ovule  is  attached 
to  the  walls  of  its  nursery,  as  one  may  see  by  looking 
at  the  peas  in  a  pod,  and  is  fed  from  the  leaves.  But 
unless  it  receives  also  the  liquid  contained  in  the  pollen- 


Blossom  and  Seed 


7 


grain,  it  remains  lifeless,  and  sooner  or  later  shrivels  and 
perishes. 

The  quantity  of  pollen  prepared  and  needed  for  the 
ovules  varies  very  greatly  in  different  plants.  The  violet, 
for  instance,  produces  about  a  hundred  grains  in  each  blos- 
som, and  the  poppy  more  than  three  million  and  a  half. 
Some  ovules  need  only  two  or  three  grains  of  pollen  to 
quicken  them,  and  others  several;  some  of  the  foreign 
orchids  bear  as  many  as  seventy-four  million  seeds,  and 
though  they  are  very  small,  each  seed  requires  the  con- 
tents of  about  twenty  grains  of  pollen  to  fertilize  it;  so 
that  the  quantity  produced  is  necessarily  very  large. 
Moreover,  a  good  deal  more  is  required  than  the  plant 
itself  needs,  as  a  considerable  margin  must  be  allowed  for 
waste,  some  being  blown  away  by  the  wind,  some  washed 
away  by  rain,  and  not  a  little  consumed  by  bees  and  other 
insects. 

Since  the  pistil  with  its  sticky  tip  stands  in  the  middle 
of  the  blossom  all  ready  to  catch  and  hold  fast  the  pollen 
which  is  discharged  by  the  surrounding  dust-spikes,  it 
would  seem  that  there  could  be  little  difficulty  about  the 
matter,  and  that  stamens  and  pistils  might  safely  be  left 
to  manage  it  without  help.  But  there  are  various  obsta- 
cles in  the  way  of  this  apparently  simple  arrangement. 

In  the  first  place,  even  though  stamens  and  pistil  be 
most  conveniently  placed,  as  it  might  seem,  for  the  very 
purpose  of  giving  and  receiving  pollen,  it  does  not  follow 
that  they  are  so.  For  where  is  the  use  of  their  being 
within  easy  reach  of  one  another  if  they  are  not  both 
ready  to  act  at  the  same  time.?  And  this  is  a  thing  which 
happens  very  frequently  indeed.  Sometimes  the  pistil  is 
ready  first;   its  tip  is  unfolded  and  sticky,  and  waiting  for 


172  The  Great  World's  Farm 

pollen,  before  that  of  the  surrounding  stamens  is  ripe 
enough  to  burst  from  the  anthers.  But  the  pistil  cannot 
go  on  waiting,  and  if  pollen  does  not  reach  it  at  the  right 
time,  it  is  of  no  use  its  coming  at  all;  the  time  is  gone  by, 
and  the  ovules  are  left  to  shrivel. 

Often,  too,  the  pollen  is  ripe  first  and  all  scattered 
before  the  pistil  is  ready  for  it;  and  here  again  the  ovules 
must  perish,  unless  pollen  is  brought  from  elsewhere. 
Even  when  pollen  and  pistil  are  ripe  together,  they  may 
be  out  of  one  another's  reach;  for  the  pistil  may  be  taller 
than  the  stamens,  or  the  anthers  may  open  outwards 
instead  of  inwards,  and  in  neither  case  will  the  pollen  be 
scattered  on  the  pistil-tip,  or  be  of  any  use  to  the  ovules. 

But  there  are  more  difficulties  even  than  these.  A 
perfect  flower,  as  has  been  said,  consists  of  a  double  set 
of  outer  and  a  double  set  of  inner  organs;  but  very  many 
flowers  are  quite  imperfect.  One  or  both  of  the  outer 
set  of  leaves  may  be  altogether  wanting,  and  one  or  other 
of  the  inner  set  may  be  also  wanting;  that  is  to  say,  some 
plants  grow  the  pistil  in  one  blossom  and  the  stamens  in 
another,  but  never  both  in  the  same  blossom;  and  others 
go  a  step  further  than  this,  and  grow  their  pistils  and 
stamens  not  merely  in  different  blossoms,  but  on  different 
plants. 

Those  plants  or  blossoms  which  bear  stamens  only 
are  of  course  barren,  for  they  possess  no  ovules,  as  they 
possess  no  pistils;  and  those  which  bear  pistils  only  are, 
or  may  be,  fertile,  since  they  possess  ovules,  which  may 
become  seeds  provided  pollen  be  brought  to  them  from 
another  blossom  or  plant,  but  not  otherwise. 

And  then  again,  even  when  a  plant  bears  perfect  flow- 
ers with  both  pistils  and  stamens,  it  not  unfrequently  hap- 


Blossom  and  Seed  lyj 

pens  that  pollen  from  their  own  blossom,  or  from  another 
blossom  on  the  same  stalk,  does  not  suit  the  ovules. 
Some  which  are  fertiHzed  by  the  pollen  of  their  own  blos- 
som, close-fertiHzed,  as  it  is  called,  do  well,  and  the  seed 
is  plentiful;  but  in  most  cases  it  is  poor,  and  even  worth- 
less. Sometimes  the  pollen  from  a  blossom  on  the  same 
stalk  actually  has  the  effect  of  poison,  and  when  applied 
to  the  pistil-tip,  causes  it  to  shrivel  and  decay,  and  makes 
the  petals  drop;  sometimes,  again,  it  does  neither  good  nor 
harm  directly;  it  does  not  poison  and  it  does  not  fertilize, 
but — which  is  equally  injurious — it  prevents  any  other 
pollen  received  afterwards  from  having  any  effect,  so  that 
in  either  case  the  ovules  are  equally  sure  to  shrivel. 
Then,  further,  there  are  some  plants,  as,  for  instance, 
certain  of  the  passion-flowers,  whose  ovules  cannot  be 
converted  into  seeds  unless  they  receive  pollen  not  merely 
from  another  plant  of  the  same  species,  but  from  another 
plant  of  a  different  species — a  passion-flower,  but  a  differ- 
ent species  of  passion-flower. 

Such,  then,  being  some  of  the  many  arrangements  by 
which  it  is  made  difficult  or  impossible  for  ovules  to  be 
fertilized  by  pollen  from  their  own  blossom,  or  from  a 
blossom  on  the  same  stalk,  one  must  conclude  that  there 
is  some  reason  for  them,  and  that  seed  is  the  better  for 
being  cross-fertilized — fertilized,  that  is,  by  pollen  from 
another  plant.  And  so,  indeed,  it  proves;  for  if  cross- 
fertilized  and  self-fertilized  seeds  be  sown  together,  it 
generally  happens  that  the  former  grow  up  so  much  the 
stronger  as  quite  to  overpower  the  rest. 

As  a  rule,  then,  cross-fertilized  seed  produces  much 
more  vigorous  plants  than  self-fertilized  seed  does.  But 
still,  as  wild   plants  have  to  keep  their  own  place  in  the 


174  The  Great  World's  Farm 

world,  which  they  cannot  do  without  offspring,  it  is  better 
for  them  to  have  some  seed,  even  poor  seed,  rather  than 
none  at  all.  And  to  insure  this  some  plants  manage  to 
bear  seed  of  both  sorts;  some  fertilized  by  the  pollen  of 
its  own  blossom,  some,  if  possible,  by  that  brought  from 
outside,  so  that  if  by  any  chance  the  latter  should  fail, 
they  may  stiU  have  something  to  fall  back  upon. 

There  is,  for  instance,  that  ubiquitous  little  plant,  the 
common  chickweed,  weak-stemmed  and  fragile-looking, 
but  not  in  the  smallest  danger  of  dying  out,  for  it  goes  on 
sowing  itself  through  many  m.onths  of  the  year.  Its  first 
crop  of  seed  is  fertilized  quite  early  in  the  spring,  so  early 
that  the  plant  is  left  to  itself,  and  has  to  make  the  best  of 
its  own  pollen,  which  it  does  in  the  most  thrifty  way  pos- 
sible. The  pollen  is  never  scattered,  so  there  is  no  waste, 
but  while  still  in  the  anther-sacs,  it  sends  out  tubes  in  the 
direction  of  the  pistil-tip,  which  it  reaches  without  fail. 
This  process  takes  place  while  the  flowers  are  still  only 
buds,  so  that  pollen  and  tubes  are  carefully  protected. 
The  seed  thus  produced  may  be  poor,  much  of  it  may 
even  be  useless,  but  at  least  what  there  is,  is  better  than 
none;  and  later  in  the  season,  if  circumstances  are  favor- 
able, better  seed  will  be  produced  by  pollen  brought  from 
other  plants. 

Generally  speaking,  pollen-grains  do  not  begin  to  swell 
until  they  actually  touch  the  moist  tip  of  the  pistil,  but  in 
these  early  blossoms  of  the  chickweed  and  some  other 
plants,  they  never  leave  the  anthers.  The  sweet  violet, 
in  like  manner,  bears  some  buds,  smaller  than  the  rest, 
which  never  open.  These  produce  but  a  few  grains  of 
pollen,  as  there  is  no  waste  to  be  allowed  for,  and  they 
send  out  long  tubes  without  leaving  the  anthers^ 


Blossom  and  Seed  17  r 

The  dog-violet,  on  the  other  hand,  as  it  does  not  resort 
to  this  device,  is  quite  seedless,  unless  pollen  be  brought 
to  it ;  and  other  plants  are  much  worse  off,  and  can  never 
set  seed  at  all  in  this  country,  being  unable  to  make  use 
of  their  own  pollen,  and  not  finding  here  the  messengers 
which,  in  their  native  land,  bring  them  pollen  from  other 
plants.  The  greater  periwinkle  is  one  of  these,  and  never 
has  seed. 

As  has  been  mentioned,  some  blossoms  have  pistils  so 
much  longer  than  the  stamens  that  it  seems  impossible  for 
the  pollen  of  the  one  to  reach  the  tip  of  the  former.  This 
is  the  case  with  the  colchicum,  whose  mauve-colored  blos- 
soms are  much  like  those  of  the  crocus.  But  when  the 
pollen  is  ripe  and  the  anthers  have  burst  some  of  the  dust 
is  rubbed  off  upon  the  inside  of  the  petals  when  the  flower 
closes,  as  it  does  every  night,  several  times  in  succession. 
Meanwhile  the  petals  lengthen  so  much,  that  when  the 
blossom  closes  for  the  last  tim.e,  the  first  spots  of  pollen 
are  brought  up  to  a  level  with  the  tip  of  the  pistil  and  are 
pressed  against  it,  with  the  result  that  some  of  the  grains 
adhere  to  the  sticky  surface  and  soon  begm  to  grow,  at 
the  rate  of  something  more  than  an  inch  in  an  hour. 

In  the  case  of  the  colchicum,  the  ovules  are  a  very 
long  way  from  the  pistil-tip — as  much  as  thirteen  inches — 
but  they  are  reached  in  about  twelve  hours.  This  takes 
place  at  latest  at  the  beginning  of  November;  but  for 
some  reason,  perhaps  because  it  needs  warmth,  the  germ 
or  embryo  does  not  begin  to  form  in  the  ovules  until  the 
following  May. 

The  ovules  of  the  American  oak  wait  almost  a  year 
after  the  entrance  of  the  pollen-tube  before  they  begin  to 
develop,  and  then  take  another  year  to  ripen. 


176  The  Great  World's  Farm 

Why  should  the  pollen-tube  always  grow  with  its  end 
directly  towards  the  very  narrow  opening  by  which  it  is  to 
enter  the  ovule? 

For  the  ovule  is  often  far  away — what,  considering  the 
size  of  the  pollen-grain,  may  be  called,  without  exaggera- 
tion, hundreds  of  miles  away — while  the  door  by  which 
alone  the  tube  can  find  entrance  is  the  merest  point. 
Indeed,  the  ovules  themselves  are  often  mere  specks,  and 
usually  they  are  placed  in  what  looks  like  a  most  inaccess- 
ible position,  quite  inclosed  in  the  ovary.  Often,  too, 
there  are  hundreds,  and  even  thousands  of  ovules  in  one 
ovary,  each  of  which  receives  at  least  one  pollen-tube,  in 
some  cases  more. 

Even  when  it  has  taken  the  first  turn  downwards  in  the 
right  direction  there  is  plenty  of  room — either  on  its  way 
down  the  pistil  stalk  or  when  it  reaches  the  ovary — for 
the  tube  to  go  astray.  But  instead  of  doing  so  it  makes 
unerringly  for  its  mark,  and  we  can  only  conclude  that 
some  definite  arrangements  exist  by  which  it  is  directed 
into,  and  kept  in,  the  right  way. 

QUESTIONS  FOR  REVIEW 

1.  How  are  different  classes  of  plants  affected  by  the  fruit- 
bearing  process? 

2.  How  do  bulbous  plants  prepare  for  their  bloss6ms? 

3.  What  peculiarities  has  the  American  aloe? 

4.  What  relation  has  the  size  of  the  blossom  to  the  size  of 
the  plant? 

5.-  Describe  the  peculiarities  of  the  largest  known  blossom. 

6.  Describe  the  chief  parts  of  a  flower. 

7.  What  are  double  blossoms? 

8.  Describe  the  pollen-grains. 

9.  How  does  the  pollen  reach  the  ovules? 


Blossom  and  Seed  \y^ 

10.  What  difficulties  prevent  many  plants  from  bein^  fer- 
tilized by  their  own  stamens? 

11.  What  fact  is  illustrated  by  the  chickweed? 

12.  Describe  the  process  of  fertilization  in  the  colchicum. 

13.  How  are  the  wonderful  processes  of  nature  illustrated 
by  the  pollen-tube? 


CHAPTER  XY 

THE  GOLDEN   RULE  FOR  FLOWERS 

''Get  fertilized!  cross-fertilized  if  you  can,  self-fer- 
tilized if  you  must,"  that  is  nature's  golden  rule  for 
flowers. 

We  have  mentioned  only  a  few  of  the  curious  and  inter- 
esting arrangements  by  which  the  pollen  is  in  very  many 
cases  prevented  from  coming  in  contact  with  the  ovules 
of  its  own  blossom;  but  enough  has  been  said  to  show 
that  this  self-fertilization  is  generally  discouraged,  and 
made  in  many  cases  either  difficult  or  altogether  impossible. 

We  have  now  to  see  how  cross-fertilization  is  provided 
for,  and  by  what  messengers  pollen  is  conveyed  from  one 
blossom  to  another.  These  messengers  are  wind,  insects 
of  many  kinds,  birds,  and  even  in  some  instances  that 
most  unlikely  of  gardeners,  the  ill-reputed  snail. 

Plants  which  depend  upon  the  wind  for  bringing  them 
the  needful  pollen  have  small,  inconspicuous,  and  gen- 
erally scentless  blossoms;  bright  colors,  sweet  scents,  and 
honey,  being  usually  confined  to  those  plants  which  need 
the  services  of  birds  and  insects.  The  pistil-tips  or  stig- 
mas of  the  former  are  also  especially  adapted  for  catching 
and  holding  the  grains  of  pollen  blown  upon  them,  for 
they  are  either  divided  into  plumes  or  feathers,  or  are 
plentifully  beset  with  hairs.  Grasses  and  sedges  are 
chiefly  wind-fertilized;  and  so,  too,  are  many  trees,  such 
as  the  oak,  beech,  hazel,  birch,  elm,  poplar,  and  pine,  all 

178 


The  Golden  Rule  for  Flowers  179 

of  which  blossom  early  in  the  year,  often  before  there  are 
any  leaves  to  interfere  with  the  scattering  of  the  pollen: 
and  they  mostly  bear  pollen  and  ovules  in  separate  blos- 
soms, some  on  the  same  tree,  some  on  different  trees. 

The  pollen-bearing,  or  staminate  blossoms  of  these 
trees  grow  together  in  large  numbers,  in  the  form  of 
tassels  or  catkins,  which  wither  and  drop  when  their  pollen 
is  scattered  and  their  work  done. 

The  catkins  of  the  hazel  contain  more  than  a  hundred 
blossoms,  having  no  petals,  but  ten  or  twelve  stamens 
each.  The  blossoms  containing  the  ovules  grow  on  the 
same  tree,  but  they  have  no  petals  either,  and  are  so  small 
as  almost  to  escape  notice,  for  they  look  like  nothing  but 
small,  scaly  buds,  with  tiny  crimson  tufts  on  the  top. 
These  crimson  tufts  are  the  stigmas,  outspread  on  purpose 
to  catch  the  grains  of  pollen  as  they  float  by. 

Pines,  on  the  other  hand,  have  not  only  no  petals,  but 
no  pistil-stalks,  and  not  even  stigmas  either;  all  that  there 
is  of  the  pistil  being  the  ovary,  which  is  scale-shaped  and 
open,  so  that  the  pollen  falls  directly  upon  the  ovules 
within  it.  As  the  ovules  develop  into  seeds  and  grow, 
the  scales  that  bear  them  grow  also,  and  ripen  into  fir- 
cones. 

Pollen  which  has  to  be  carried  by  the  wind  is  light,  dry, 
and  powdery,  and  is  produced  in  very  large  quantities  to 
allow  for  the  unavoidable  waste.  It  is  carried  far  and 
wide,  and  the  air  is  often  filled  with  it,  especially  in  the 
neighborhood  of  forests.  Masses  of  pine-pollen  are  often 
found  in  America  as  much  as  three  or  four  hundred  miles 
away  from  any  trees  wiiich  could  have  produced  it.  Of 
course,  where  plants  are  dependent  upon  the  wind  for 
pollen,  they  are  liable  to  have  a  great  variety  of  it  brought 


I  80  The  Great  World's  Farm 

to  them;  but  this  does  not  hurt  them,  for  unless  the  right 
kind  comes  it  simply  has  no  effect  whatever.  But  as  it  is 
of  great  importance  to  these  plants  not  to  miss  any  chance 
of  the  right  pollen,  and  as  the  wind  blows  at  all  times, 
night  and  day,  they  never  close,  many  being  unable  to  do 
so  from  want  of  petals,  so  that  they  are  always  ready  to 
receive  it. 

Among  the  trees  which  are  fertilized  at  least  in  part  by 
the  wind  are  the  palms,  whose  blossoms  are  small  and 
dull-looking,  and  inclosed — thousands  of  them  together — 
in  a  sheath,  something  like  that  of  the  arum.  But  some 
of  the  palms  are  very  strongly  scented,  and  when  the 
sheath  opens  it  is  a  center  of  attraction  to  a  buzzing  cloud 
of  flies,  small  beetles,  and  other  insects. 

The  date-palm  bears  ovules  and  pollen  on  separate 
trees;  and  when  date-stones  are  planted  it  is  found  that 
instead  of  coming  up  half  of  one  sort  and  half  of  the 
other,  there  are  more  of  the  fruit-bearing  than  of  the 
unfruitful  trees  among  them. 

However,  one  pollen-bearing  tree  is  well  able  to  supply 
more  than  one  ovule-bearing  tree,  and  in  their  wild  state 
the  trees  have  no  difficulty  in  obtaining  all  that  they  want. 
But  when  they  are  cuUivated  then  they  require  help, 
though  trees  of  both  kinds  grow  in  the  same  plantation. 
The  fact  is  mentioned  by  many  writers,  from  Pliny  down- 
wards, though  without  explanation;  and  in  aU  the  planta- 
tions part  of  the  work  consists  in  climbing  the  trees,  first 
to  collect  pollen-bearing  blossoms,  and  next  to  dust  with 
them  the  little  ovules,  which  are  about  as  large  as  peas, 
and  he  exposed  in  the  center  of  the  other  blossoms,  not 
inclosed  in  an  ovary.  If  this  is  not  done  the  date  crop 
fails. 


The  Golden  Rule  for  Flowers  i8i 

During  Napoleon's  campaigns  in  Egypt,  the  natives 
not  having  much  leisure  to  attend  to  husbandry,  the  plan- 
tations about  Cairo  were  neglected,  and  although  the  trees 
blossomed  as  usual  the  eatable  dates  were  few. 

In  the  East  dates  are  such  an  important  article  of  food, 
and  the  failure  of  the  crop  such  a  serious  loss,  that 
nations  at  war,  and  desirous  of  inflicting  as  much  injury 
as  possible  upon  one  another,  were  in  the  habit  of  cutting 
down  not  all  the  palms  indiscriminately,  but  those  bear- 
ing pollen.  On  one  occasion  it  is  said  that  the  Persians, 
fearing  they  might  be  injured  in  this  way  during  a  civil 
war,  took  the  precaution  of  collecting  the  pollen  from  the 
trees,  kept  it  in  close  vessels  for  nineteen  years,  and  made 
successful  use  of  it  when  peace  was  restored. 

The  Arabs  are  said  always  to  keep  some  of  the  un- 
opened sheaths  containing  pollen  from  year  to  year,  in 
case  of  any  failure  in  the  blossoms. 

It  has  been  mentioned  that  pollen  may  often  be  borne 
long  distances  by  the  wind,  and  this  has  been  exemplified 
in  a  remarkably  interesting  way  by  the  case  of  a  date-palm 
growing  near  Otranto.  The  palm  is  not  a  native  of  Italy, 
and  though  introduced,  does  not  grow  wild;  and  this 
specimen,  being  the  only  one  of  its  kind  in  the  neighbor- 
hood, was  barren  for  years.  But  at  last,  one  year,  the 
young  dates,  instead  of  shriveling  as  usual,  remained  on 
the  tree  and  grew  to  their  proper  size;  and  then  it  was 
found  that  a  date-tree  had  flowered  that  same  year  for  the 
first  time  at  Brindisi,  some  forty  odd  miles  away,  and  had 
borne  pollen-blossoms.  This  pollen,  therefore,  had  no 
doubt  been  carried  by  the  wind  to  the  tree  at  Otranto. 

The  case  of  another  solitary  date-tree,  growing  at  Mar- 
tinique, in  the  West  Indies,  is  also  interesting,  though  in 


1 82  The  Great  World's  Farm 

another  way.  For  this  tree  bore  eatable  fruit  without 
being  fertihzed,  but  though  the  dates  might  be  eaten  the 
stones  would  not  grow,  for  the  seeds  were  imperfect,  and 
contained  no  germ. 

The  fruit  of  a  plant,  botanically  speaking,  is  the  ripened 
pistil,  or  rather  that  part  of  the  pistil  which  contains  the 
ovules.  Sometimes,  as  in  the  case  of  the  various  kinds 
of  corn,  it  is  the  ripened  ovules,  the  seeds,  which  are  the 
eatable  part  of  the  fruit,  the  ovary  in  which  they  are  con- 
tained being  a  mere  husk.  In  the  various  gourds,  on  the 
other  hand,  the  ovary  itself  grows  enormously  and  be- 
comes fleshy.  So,  too,  with  apples,  pears,  peaches,  necta- 
rines, plums,  and  oranges,  the  swollen,  ripened  ovary 
containing  the  seed  is  the  part  best  worth  eating;  and  it 
has,  therefore,  been  the  gardeners'  object  to  increase  its 
size  and  improve  its  flavor.  In  the  almond,  the  ovary 
remains  a  mere  wooly  skin  without  edible  flesh;  in  the 
horse-chestnut  it  is  a  tough,  thick,  and  prickly  skin, 
equally  uneatable;  in  the  filbert  and  beech-nut  it  is  a  hard 
shell;  and  in  the  coconut  it  consists  of  fiber.  Whether 
husk,  shell,  skin,  flesh,  or  fiber,  however,  the  whole  ovary 
with  the  ripened  ovules  is  properly  the  plant's  fruit. 

Generally  speaking,  the  growth  of  the  ovary,  as  well  as 
of  the  ovule?,  depends  upon  pollen,  and  when  the  ovules 
are  fertilized  and  begin  to  grow,  the  ovary  begins  to 
develop  also,  and  not  until  then. 

But  it  is  not  always  so.  Among  the  plants  belonging 
to  the  order  of  Liliaceae,  which  includes,  besides  liUes, 
the  hyacinth,  tulip,  garlic,  onion,  and  others,  it  is  a  com- 
mon thing  for  the  ovary  to  begin  growing  actively  before 
the  pollen-tubes  have  reached  the  ovules — before  they  are 
fertilized,   therefore — though   not  before   the  tubes  have 


The  Golden  Rule  for  Flowers  183 

begun  to  penetrate  downwards  through  the  style.  In 
these  cases  the  ovary  seems  to  be  excited  to  growth  by 
the  pollen,  though  not  in  the  usual  way,  and  before  the 
ovules  are  affected. 

But  in  many  plants  the  ovary,  and  even  ovules,  may  be 
fully  developed,  altogether  without  pollen;  though  in  this 
case  the  ovules  do  not  become  seeds  any  more  than  the 
** stones"  of  the  Martinique  date  becomes  seeds,  and  no 
plant  can  be  raised  from  them. 

Among  the  plants  which  ripen  the  ovary  without  the 
help  of  pollen  are  the  Zante  "currant"  (really  a  small 
grape),  many  Maltese  oranges,  and  some  kinds  of  apple. 

While  some  ovules  are  so  independent  as  to  be  able  to 
grow  to  the  size  of  seeds,  and  even  to  assume  the  appear- 
ance of  seeds,  without  being  fertihzed,  there  are,  on  the 
other  hand,  some — as,  for  instance,  those  of  the  orchids — 
which  are  not  even  formed  until  the  pollen-tubes  begin  to 
grow  towards  the  place  where  they  should  be.  The  pollen 
in  these  cases  not  only  fertihzes  them,  but  though  still  at 
a  distance  is  the  means  of  bringing  them  into  being. 

Of  course,  as  pollen  is  so  light,  and  easily  blown  about, 
many  plants  may  at  times  be  fertilized  by  the  wind,  besides 
those  which  are  especially  dependent  upon  it.  Not  many, 
one  would  suppose,  are  fertilized  by  water;  yet  there  are 
one  or  two  instances  of  this  too  curious  to  be  passed  over. 

One  of  these  is  that  of  a  small  water-plant,  nearly  re- 
lated to  the  duckweeds,  which  bears  two  blossoms  inclosed 
together  in  a  boat-shaped  sheath,  which  floats  upon  the 
water.  In  the  upper  part  of  the  sheath  is  a  perfect  pistil, 
with  its  ovary,  short  stalk,  and  stigma;  in  the  lower  part 
are  the  anthers  containing  pollen,  which  cannot  by  any 
possibility  reach  the  stigma  unless  rain  happens  to  fall 


184  The  Great  World's  Farm 

when  it  is  ready.  If  it  does,  the  sheath  is  gradually  filled 
with  water,  and  the  pollen  is  floated  up  till  it  reaches  the 
right  place. 

There  is  a  still  more  curious  arrangement  in  the  case 
of  the  Vallisneria,  which  grows  in  the  ditches  in  Italy,  and 
is  well  known,  though  not  in  a  flowering  state,  in  fresh- 
water aquariums.  This  plant  bears  its  pistillate  and  stami- 
nate  blossoms  on  separate  roots,  which,  however,  seem  to 
grow  near  one  another.  The  pistillate,  fruit-bearing  blos- 
som grows  on  a  long,  slender  stalk  twisted  like  a  cork- 
screw, which  uncurls  and  raises  the  bud  just  above  the 
surface  of  the  water  when  it  is  about  to  open.  The 
barren,  staminate,  or  pollen-bearing  flowers,  grow  in  great 
numbers  on  short,  upright  stalks  under  water;  but  just 
about  the  time  when  the  other  blossoms  up  above  open 
and  want  their  help,  these  buds  loose  themselves  from 
their  stalks  and  rise  up  like  little  air-bubbles,  opening  sud- 
denly when  they  reach  the  surface.  Here  they  float  about 
on  the  water  among  the  pistillate  blossoms  in  such  num- 
bers that  they  often  quite  cover  them,  and  by  this  means 
convey  to  them  the  necessary  pollen.  When  this  has  been 
received,  the  corkscrew  stalks,  which  are  often  as  much 
as  ten  feet  long,  curl  up  as  before,  and  the  fertilized  blos- 
soms sink  down  again  to  ripen  their  fruit  under  water. 

We  must  now,  however,  turn  to  the  insects,  among 
which  bees  have  a  foremost  claim  upon  our  attention, 
since  none  are  more  generally  useful  in  carrying  on  the 
very  important  work  of  fertilization.  Creeping  insects  are 
not,  as  a  rule,  useful  visitors  for  flowers,  as  any  grains  of 
pollen  which  they  may  pick  up  by  the  way  are  liable  to  be 
brushed  off  again  before  they  reach  a  blossom  which  might 
be  benefited.     But  flying  insects  of  all  kinds,  even  to  the 


The  Golden  Rule  for  Flowers  185 

smallest  flies  and  midges,  when  once  dusted  with  pollen, 
are  almost  sure  to  convey  a  few  grains  to  the  next  blos- 
som upon  which  they  alight.^ 

Pollen  is  of  vital  importance  to  the  plants  themselves, 
besides  serving  as  food  to  bees  and  other  insects;  but 
nectar,  so  far  as  appears,  is  of  no  use  to  the  plant  except 
as  serving  to  attract  useful  visitors;  and  the  same  may  be 
said  of  sweet  scents  and  brightly  colored  petals.  All  these 
are,  in  fact,  the  one  baits,  the  other  signals,  which  the 
plant  puts  forth  to  make  known  to  those  who  understand 
the  language  where  pollen  and  nectar  may  be  found. 

"Good  entertainment  for  bees  and  butterflies"  is  what 
the  bright  colors  mean;  and  where,  as  is  often  the  case, 
the  nectar  is  concealed  in  some  deep  and  safe  recess  where 
wet  cannot  injure  it,  many  flowers  have  lines  or  dots  upon 
some  of  their  petals  to  point  out  where  it  may  be  found, 
and  so  save  their  visitors'  time. 

Many  bees  have  a  regular  pollen-brush  of  thick  hairs 
under  their  tails,  with  which  they  sweep  up  the  grains; 
and  even  when  their  object  is  nectar,  not  pollen,  they  are 
almost  sure  to  carry  off  a  few  grains  by  brushing  against 
the  anthers  of  the  blossom  they  are  visiting.  For  all  bees 
are  more  or  less  covered  with  hairs,  some  of  which,  being 
webbed,  are  especially  adapted  for  holding  the  pollen- 
grains,  while  the  grains  themselves  cling  all  the  better  for 
the  spines  and  hairs  with  which  they  are  often  beset. 

Small  insects  are  useful  for  fertilizing  small  flowers, 
but  they  may  light  upon  a  large  flower,  creep  in,  and  even 
rob  it  of  nectar,  without  coming  into  contact  with  the 
pollen  at  all,  which  is  almost  impossible  in  the  case  of  the 
larger  species  of  bees,  with  their  hairy  bodies.  The  bee, 
too,  has  another  recommendation:   it   has  to   visit   many 


1 86  The  Great  World's  Farm 

flowers  before  its  crop  is  filled  with  nectar,  and  both  hive- 
bees  and  humble-bees,  especially  the  latter,  seem  generally, 
though  not  invariably,  to  confine  their  visits  to  one  kind 
of  flower  on  each  journey — a  very  important  matter,  as 
pollen  of  difl"erent  sorts  would  in  most  cases  be  useless. 

Of  course  the  bee  may,  and  does,  convey  pollen  from 
blossom  to  blossom  of  the  same  plant,  which  may  produce 
self-fertilization  of  a  sort;  but  when  it  has  visited  all  the 
blossoms  on  one  plant,  and  flies  off  to  another,  the  first 
blossoms  visited  there  must  needs  stand  a  good  chance  of 
receiving  pollen  from  the  last  of  the  former. 

That  the  work  thus  done  by  bees  is  in  many  cases  abso- 
lutely indispensable  there  is  ample  proof,  though  we  may 
not  always  recognize  it. 

The  bean-crop  failed  in  Nicaragua  just  for  lack  of  the 
right  sort  of  bee;  and  often  when  the  young  gooseberries, 
or  what  should  be  gooseberries,  wither  and  drop  in  early 
spring,  instead  of  swelling  as  they  ought  to  do,  it  is  not 
so  much  because  they  have  been  nipped  by  the  frost  as 
that  the  frost  has  kept  the  bees  at  home.  For  the  pollen 
and  pistils  of  the  gooseberry-blossoms  ripen  at  different 
times,  so  that  the  one  must  be  brought  to  the  other  if  the 
ovules  are  to  be  fertilized;  and  if  this  is  not  done,  neither 
they  nor  the  berry  containing  them  can  grow  to  their 
proper  size. 

One  year  there  was  a  remarkable  scarcity  of  holly-ber- 
ries in  different  parts  of  the  country,  which  some  people 
thought  was  accounted  for  by  the  cold  weather  in  the 
early  part  of  the  year.  But  the  holly  is  a  very  hardy 
shrub,  and  grows  in  Norway  as  far  north  as  62°,  so  that 
it  was  not  likely  to  have  suffered  from  an  English  spring. 
On  the  other  hand,  bees  were  remarkably  rare  that  season ; 


The  Golden  Rule  for  Flowers  187 

and  as  the  holly  grows  its  stamens  and  pistils  mostly  on 
different  plants,  the  dearth  of  berries  was  doubtless  owing 
to  the  absence  of  bees. 

For  though  holly-bloom  are  insignificant,  they  are  fer- 
tilized chiefly  by  bees,  and  not  by  wind,  pollen  having  been 
observed  by  Mr.  Darwin  on  many  pistil-tips,  which  must 
have  been  brought  from  a  tree  sixty  yards  away,  and  could 
not  have  been  conveyed  by  the  wind,  since  it  was  blowing 
in  the  wrong  direction. 

The  year  that  the  holly-berries  failed,  the  crop  of 
clover-seed  failed  also  in  some  parts,  and  no  doubt  from 
the  same  cause.  For  though  some  clovers  manage  to 
fertilize  themselves  more  or  less,  there  is  a  very  marked 
difference  in  the  quantity  of  seed  borne  by  the  plants, 
according  as  they  are  kept  covered,  and  out  of  the  way  of 
insects,  or  not. 

A  hundred  heads  of  common  red  clover  bear  about  two 
thousand  seven  hundred  and  twenty  seeds  among  them; 
but  a  hundred  heads  covered  with  a  net  on  one  occasion, 
to  keep  off  the  bees,  had  not  one  single  seed.  This  com- 
mon red  clover  has  a  tube,  too  long  to  be  sucked  by  the 
hive-bee  until  it  has  been  mown,  when  the  second  crop  of 
blossoms  are  said  to  be  rather  smaller,  and  its  first  crop 
is  dependent  on  the  humble-bee.  A  very  slight  difference 
in  length  makes  just  all  the  difference  as  to  the  species  of 
bee  which  is  able  to  extract  nectar  from  the  blossom. 
The  brilliant  crimson  clover  is  frequented  by  the  hive-bee, 
its  tube  being  shorter  than  that  of  the  common  red  kind. 

Strawberry  plants  are  altogether  dependent  upon  bees 
for  the  perfecting  of  their  fruit,  even  where  pollen  and 
ovules  are  produced  in  the  same  blossoms.  In  one 
species  of  strawberry,  the  true  hautbois,  they  are  borne 


1 88  The  Great  World's  Farm 

by  different  plants;  and  in  the  great  market- gardens  of 
America,  where  this  is  grown,  it  is  usual  to  plant  one  row 
of  barren  plants  to  every  three  rows  of  fertile  ones,  leaving 
the  bees  to  do  the  rest. 

A  great  deal  has  to  be  done  to  insure  the  thorough 
fertilization  of  the  strawberry-ovules,  for  there  are  from  a 
hundred  to  three  hundred  in  each  fertile  blossom,  and 
there  are  an  equal  number  of  pistils.  The  pistils  are  set 
upon  a  cone-shaped  receptacle  in  the  center  of  the  blos- 
som; each  one  contains  in  its  ovary  a  single  ovule,  and 
the  ovary  and  ovule  ripening  together,  develop  into  a  tiny 
nut,  which  is  the  fruit  properly  speaking. 

As  the  nuts  grow,  the  conical  receptacle  on  which  they 
are  set  grows  too,  and  becomes  soft,  fleshy,  and  sweet, 
forming  what  we  erroneously  call  the  * 'berry." 

But  if  the  "berry"  is  to  grow  properly,  every  one  of 
the  pistils  must  receive  a  few  grains  of  pollen,  and  if  any 
are  left  out,  the  ovules  belonging  to  them  do  not  grow, 
and  the  part  of  the  receptacle  which  surrounds  them  does 
not  grow  either,  but  remains  hard.  The  hard  spots  some- 
times found  in  strawberries,  with  a  number  of  little  "seeds" 
crowded  together,  are  due  simply  to  the  fact  that  the 
ovules  have  not  been  fertilized,  and  have  withered  instead 
of  growing. 

So,  too,  with  the  raspberry.  Each  one  of  the  sixty  or 
seventy  little  fruits  composing  the  "berry"  depends  upon 
pollen  for  the  power  of  developing  not  only  its  seed,  but 
also  the  sweet,  juicy  envelope  surrounding  each  seed. 
Towards  the  end  of  the  season  these  often  fail  and  wither, 
because  the  bees  are  either  dying  off,  or  do  not  care  to 
come  out  unless  the  weather  is  tempting. 

Then,  again,  with  apples;   one  may  often  see  an  apple 


The  Golden  Rule  for  Flowers  189 

which  is  deformed,  having  grown  on  one  side;  and  the 
reason  here,  too,  is  similar. 

The  calyx  of  the  apple-blossom  is  a  tube  which  spreads 
out  at  the  top  into  five  leaf-like  divisions.  Inside  the 
tube,  and  joined  to  it,  are  the  ovaries,  which  together  form 
the  horny  core.  When  the  stigmas  are  all  properly  dusted 
with  pollen,  each  ovary,  with  its  two  pips,  begins  to  grow; 
but  if  nothing  else  grew,  there  would  be  no  apple,  only  a 
horny  seed-vessel,  the  only  eatable  part  of  which  would 
be  the  seeds.  But  the  calyx  inclosing  the  core  grows  too, 
and  so  does  the  top  of  the  stalk  from  which  it  springs; 
and  it  is  these  which  together  form  the  apple. 

If,  however,  one  of  the  stigmas  be  by  chance  left  with- 
out pollen,  then  the  ovary  belonging  to  it,  with  its  two  pips 
and  the  part  of  the  calyx  next  to  it,  does  not  grow,  and 
the  apple  is  misshapen. 

There  is  a  French  apple  called  the  S.  Valery  apple, 
which  is  remarkable  for  having  a  double  calyx  and  a 
double  core,  with  ten  divisions,  but  no  petals,  and  only 
imperfect  stamens,  which  produce  no  pollen.  This  has  to 
come,  therefore,  from  different  varieties,  and  it  is  a  regu- 
lar custom  for  the  girls  of  S.  Valery  to  go  to  the  orchards 
in  the  spring,  taking  pollen  from  various  other  apple- 
trees,  to,  as  they  say,  ''make  their  apples."  Each  marks 
with  ribbons  her  own  fruit,  and  the  different  pollen  pro- 
duces apples  of  different  flavor,  color,  and  size,  according 
to  the  variety  of  apple  from  which  the  pollen  has  been 
taken. 

Occasionally  one  hears  of  an  apple-tree  which  indulges 
in  the  freak  of  bearing  fruit,  some  of  which  is  of  the  ordi- 
nary shape,  and  some  pear-shaped,  both  sorts  growing  on 
the  same  twigs.     In  this  case  one  must  suppose  that  the 


190  The  Great  World's  Farm 

bees  have  been  less  particular  than  usual,  and  have  dusted 
the  pistil-tips  with  pear-pollen.  So,  too,  an  orange-blos- 
som crossed  with  pollen  from  a  lemon  will  bear  fruit  which 
is  partly  orange,  partly  lemon,  with  peel  partly  of  the  one, 
partly  of  the  other. 

Among  the  many  plants  visited  by  bees,  large  or  small, 
are  the  foxglove,  mallow,  and  campanula,  all  of  which, 
though  they  grow  pistils  and  stamens  together,  ripen  them 
at  different  times.  Any  one  not  knowing  this,  and  examin- 
ing a  campanula-blossom,  would  be  puzzled  to  know  what 
could  have  become  of  the  stamens,  for  when  the  flower 
opens  they  have  generally  vanished;  the  pollen  is  there 
still,  however,  having  been  discharged  upon  the  stalk  of 
the  pistil  before  the  bud  opened,  after  which  the  stamens 
shriveled  away.  It  is  caught  and  held  by  the  hairs  with 
which  the  stalk  of  the  pistil  is  clothed,  apparently  for  the 
very  purpose  of  holding  it  until  the  bees  come  and  carry 
it  off.  When  the  pollen  is  gone,  the  tip  of  the  pistil 
unfolds  from  three  to  five  spreading  branches  which  no 
pollen  can  reach  while  they  remain  folded;  and  then,  back 
come  the  bees,  this  time  in  search  of  nectar,  but  bringing 
with  them  grains  of  pollen  in  abundance  from  other 
flowers. 

Some  pistils,  as  has  been  said,  are  actually  poisoned, 
and  others  unaffected  by  the  pollen  of  their  own  surround- 
ing stamens.  But  there  are  others  which  carry  their  likes 
and  dislikes  a  point  further  still,  and  require  pollen  not 
merely  from  the  blossoms  of  another  plant,  but  from  blos- 
soms whose  stamens  grow  at  exactly  the  right  height ;  and 
if  it  comes  from  stamens  too  short  or  too  long  they  can 
make  little  if  any  use  of  it. 

There  is,   for   instance,  the    great    purple    loosestrife, 


The  Golden  Rule  for  Flowers  191 

whose  tall,  handsome  spikes  of  blossom  light  up  the  river 
banks.  The  pistils  and  stamens  of  this  plant  are  of  three 
different  sizes,  but  they  correspond  exactly  in  height,  long 
pistils  with  long  stamens,  short  with  short,  and  middle- 
sized  with  middle-sized.  The  long  stamens  have  emerald- 
green  pollen,  the  others  yellow;  and  the  grains  vary  in 
size  with  the  length  of  the  stamens,  the  longer  the  stamens 
the  larger  the  grains;  for  the  larger  grains  are  destined 
for  the  longer  pistils,  and  have,  of  course,  to  send  out 
longer  tubes  in  order  to  reach  the  ovules. 

A  bee  entering  a  blossom  in  search  of  honey  is  dusted 
with  pollen  on  different  parts  of  its  body,  according  to 
the  height  of  the  stamens,  and  when  it  flies  off  to  the 
blossoms  of  another  plant,  if  the  spots  of  dust  come  in 
contact  with  pistil-tips  of  the  proper  height,  they  may  be 
caught  and  kept. 

The  red  Oxalis  is  another  of  the  plants  having  pistils 
and  stamens  of  three  sizes,  and  a  large  field  in  Brazil  con- 
taining many  acres  of  this  plant  yielded  not  a  single  seed, 
because,  though  pollen  and  insects  were  both  plentiful,  all 
the  plants  chanced  to  be  of  the  same  "form,"  as  it  is 
called — all  had  long  pistils  and  short  stamens,  or  vice 
ve7'sd,  and  the  pollen  was  of  no  use.  Other  plants  pos- 
sess similar  pecuharities,  but  we  will  mention  one  which 
all  can  examine  for  themselves,  the  common  yellow  prim- 
rose. 

The  blossom  of  the  primrose  is  a  long  tube  flattened 
out  at  the  top  into  five  divisions.  If  we  look  at  a  bunch 
of  primroses  gathered  from  different  plants,  we  see  at 
once  that  all  are  not  alike.  In  some  the  pistil,  with  a 
knob  like  a  pin's  head,  stands  up  just  out  of  the  tube;  in 
others  no  pistil  is  visible,  but  in  its  place,  just  at  the  same 


192  The  Great  World's  Farm 

height,  are  five  stamens  standing  up  Hke  teeth,  the  stalks 
being  so  very  short  that  they  are  almost  all  anther.  In 
spite  of  their  shortness,  however,  the  stamens  are  on  a 
level  with  the  long  pistil  of  the  other  blossom,  for  they  are 
attached  to  the  flower-tube,  and  for  the  long  pistil  their 
pollen  is  intended.  The  pollen-grains  of  the  stamens 
which  grow  with  the  long  pistil — but  out  of  sight,  half- 
way down  the  tube — are  intended  for  the  short  pistil, 
whose  knob  is  just  at  their  own  level,  and  accordingly, 
they  are  smaller. 

All  flowers  which  vary  in  this  way,  all  which  are  dis- 
tinguished by  color,  scent,  size,  or  irregularity  of  shape, 
are  mainly  indebted  for  fertilization  to  insects.  This  is 
the  case  with  all  bell-shaped  and  tubular  flowers,  also  with 
the  snap-dragon  and  foxgloves,  and  with  the  dead  nettles, 
lavender,  thyme,  and  all  blossoms  of  similar  shape  to 
these,  besides  many  others.  In  some  the  shapes  of  the 
blossom  and  of  the  insect  by  which  it  is  fertilized  are  as 
beautifully  and  "exactly  fitted  one  to  the  other  as  the  lock 
is  to  the  key,"  and  in  others  there  are  endless  different 
devices  for  securing,  that  the  visitor  shall  not  depart  with- 
out doing  some  service  in  return  for  the  pollen  or  nectar 
which  it  has  consumed  or  carried  off. 

In  the  common  stinging  nettle  the  four  stamens  He 
folded  down  flat  until  they  are  touched,  when  they  spring 
suddenly  up  and  scatter  their  pollen;  a  needle  inserted  in 
the  throat  of  the  common  purple  lucerne  causes  two 
stamens  instantly  to  start  up  like  a  jack-in-the-box,  the 
anthers  at  the  same  time  exploding  and  discharging  their 
dust.  A  similar  explosion  takes  place  in  the  flowers  of 
the  whin,  and  in  many  others.  In  one  plant  the  anthers 
act  like  a  pair  of  bellows,  and  on  being  touched  blow  their 


The  Golden  Rule  for  Flowers 


93 


dust  out  upon  the  insect;  in  another — the  Kalmia,  or 
American  mountain-laurel— the  stamens  rise  up  from  the 
petals  on  which  they  usually  lie  flat,  and  close  round  the 
insect,  clasping  it  and  impressing  their  pollen  upon  its 
body. 

But  the  various  arrangements  are  so  numerous  that  it 
is  impossible  to  do  more  here  than  give  the  merest  outline 
sketch  of  them,  and  for  fuller  particulars  the  reader  must 
be  referred  elsewhere. 

We  have  confined  our  attention  hitherto  chiefly  to  bees, 
because  they  are  the  most  generally  useful  of  insects,  and 
few  flowers  seem  to  come  amiss  to  them  if  only  they  can 
reach  the  nectar.  But  there  are  just  a  few  flowers  which 
they  actually  avoid.  Bees  of  all  kinds,  for  instance,  shun 
the  crown-imperial,  though  it  blossoms  in  March  and 
April,  when  bee  food  is  not  plentiful.  Gilbert  White 
noticed  a  small  bird  like  a  white-throat  running  up  the 
stems  of  this  plant  and  plunging  its  head  into  the  bells  in 
search  of  nectar,  so  it  may  be  that  it  is  fertilized  in  this 
way,  for  it  certainly  sets  seed. 

Other  flowers  disliked  by  bees  are  the  passion-flower 
and  dahlia — which  seem  to  stupefy  and  often  kill  them, 
and  above  all,  the  oleander,  whose  nectar  is  fatal.  A 
traveler  in  Hungary  and  Dalmatia,  where  the  oleander 
abounds,  could  not  remember  ever  to  have  seen  bee,  moth, 
or  butterfly  visiting  the  blossoms.  And  yet  their  bright 
rose-colored  petals  seem  to  say,  in  the  language  of  flow- 
ers, that  they  need  the  help  of  insects,  and  those,  too,  of 
a  high  order;  for  colors  have  much  meaning  in  the  flower 
language,  and  show  to  some  considerable  extent  what  kind 
of  insects  are  wanted  for  the  blossoms  which  display  them. 

White,    for  instance,    serves  to   attract  insects  of  all 


194 


The  Great  World's  Farm 


sorts;  but  bright  yellow  seems  to  be  especially  favored  by 
beetles,  and  blue  by  bees,  though  they  do  not,  of  course, 
confine  themselves  to  flowers  of  this  or  any  color.  What 
a  flower  lacks  in  color  may  often  be  more  than  made  up 
for  by  its  sweet  scent  and  abounding  nectar.  The  dull 
pink  sedum,  for  instance,  which  blossoms  in  the  autumn, 
attracts  a  swarm  of  humble-bees  and  butterflies;  though, 
as  its  flowers  are  flat  and  tubeless,  the  nectar  is  open  to 
all  comers,  and  bees  are  not  necessary  to  it. 

Yellow  is  said  to  attract  insects  of  the  lowliest  kind; 
white,  those  a  little  higher  in  the  scale;  and  pink,  red, 
lilac,  purple,  blue,  rank  higher  and  higher  as  to  the  insects 
which  they  attract,  that  very  superior  insect,  the  bee, 
being,  as  already  said,  especially  pleased  with  blue. 

It  is  the  fashion  at  present  to  say  that  the  bright  colors 
and  sweet  scents  of  flowers  exist  solely  for  the  plant's  own 
benefit,  as  the  means  of  drawing  to  it  the  insects  which 
carry  pollen  from  one  blossom  to  another.  Nevertheless, 
man  is  gratified  abundantly;  and  if  this  theory  be  correct, 
he  may  at  least  congratulate  himself  on  the  fact  that  he 
and  the  insect-world  are  of  one  mind  as  to  what  is  agree- 
able and  attractive. 

But  are  he  and  they  altogether  of  one  mind?  The 
butterfly  will  hover  about  a  lavender-bush,  attracted  by  the 
perfume,  and  so  far  man  shares  its  taste;  but  it  will  also 
go  and  drink  daintily  at  a  drain,  and  for  anything  that 
appears  to  the  contrary,  an  ill  scent  may  be  as  pleasant  to 
it  as  a  sweet  one. 

Ill-smelling  flowers,  as  well  as  sweet  ones,  have  their 
admirers,  and  are  certainly  not  especially  avoided  by 
insects;  and  flies  will  regale  themselves  upon  honey  or 
filth    with     apparently     equal     satisfaction.     Ill-smelling 


The  Golden  Rule  for  Flowers  195 

flowers  are,  however,  comparatively  very  few;  and  as  their 
colors  are  generally  deep  yellow,  orange,  brown-red,  or 
brown,  we  may  conclude  that  they  are  not  frequented  by 
such  high-class  insects  as  bees. 

QUESTIONS  FOR  REVIEW 

1.  What  classes  of  plants  are  wind  fertilized? 

2.  What  usually  are  the  characteristics  of  their  blossoms? 
Illustrate. 

3.  Give  some  peculiarities  of  the  palm. 

4.  What  is  the  true  fruit  of  a  plant?     Is  it  always  edible. 
Give  illustrations. 

5.  Does  the  ovary  ever  develop  without  pollen?     Illustrate. 

6.  Give  instances  of  the  use  of  water  in  fertilizadon. 

7.  Describe  the  way  in  which  flowers  are  fertilized  by  insects. 

8.  What  parts   of  the  strawberry  and  of  the  apple  form 
what  we  call  the  fruit? 

9.  What  peculiarity  has  the  campanula-blossom? 

10.  Describe  the  blossom  of  the  primrose.     What  fact  does 
it  illustrate? 

11.  Describe  the   effects  of   colors  in  attracting  different 
insects. 


CHAPTER    XVI 

GUESTS,  WELCOME  AND  UNWELCOME 

Bees  do  more,  on  the  whole,  for  the  fertihzation  of 
flowers  than  any  other  insects;  but  though  plentiful 
throughout  the  plains  of  Europe,  they  become  fewer  and 
fewer  as  the  traveler  ascends  the  Alps;  and  in  the  Tyrol, 
at  a  height  of  from  six  thousand  to  nine  thousand  feet,  he 
may  see  hardly  so  much  as  a  bee  a  day,  and  that  of  the 
''humble"  species  only. 

There  is,  it  is  true,  the  Ligurian,  or  yellow  Alp-bee, 
which  is  a  mountain  insect,  and  thrives  in  some  of  the 
southern  cantons  of  Switzerland  up  to  a  height  of  four 
thousand  five  hundred  feet;  but  still,  the  higher  one  goes 
the  fewer  bees  there  are  of  any  kind;  and  though  there 
are  many  beetles  and  flies,  and  very  many  moths  and 
butterflies,  there  are,  on  the  whole,  fewer  insects  of  all 
kinds  in  these  higher  regions;  and  in  the  highest,  bees  are 
almost  entirely  absent. 

Yet  the  flowers  of  the  high  Alps  are  so  intensely  bright 
in  color  that  it  is  pretty  certain  they  must  be  visited  by 
insects  of  some  sort;  and  besides  being  of  such  vivid 
colors,  the  flowers  here  are  made  still  more  striking  by 
being  massed  together  in  large  beds,  instead  of  being  scat- 
tered here  and  there.  For  the  fewer  the  insects,  the  more 
needful  it  is  to  economize  their  time  and  labor,  and  to 
avoid  the  risk,  which  solitary  plants  would  run,  of  being 
overlooked   altogether.     Here,    as   elsewhere,    "union    is 

196 


Guests,  Welcome  and  Unwelcome 


197 


strength";  and  the  butterfly  must  be  bhnd  indeed  which 
could  fail  to  notice  these  masses  of  brilliant  color. 

For  the  chief  flower-visitors  in  these  Alpine  regions  are 
moths  and  butterflies,  together  with  flies  and  beetles;  and 
it  is  curious  to  see  how  flowers  which  are  visited  by  bees 
in  the  plains  and  lower  mountain-regions  are  modified  tu 
suit  moths  or  butterflies  when  they  come  up  higher. 

Of  the  many  orchids,  for  instance,  which  grow  in  the 
plains,  all  but  very  few — four  or  five,  perhaps — are  visited 
by  bees;  but  in  the  Alps,  out  of  five  species,  all  but  one 
or  two  are  dependent  upon  butterflies  or  moths. 

Flowers  change  in  color  when  they  migrate  to  these 
higher  regions,  on  purpose  to  attract  more  notice.  Our 
pale  yellow  primrose  is  fertilized  almost  entirely  by  moths, 
but  it  might  be  overlooked  among  the  bright  flowers  of  the 
Alps  if  it  did  not  dress  more  gayly  there,  so  it  wears  bril- 
liant pink  and  magenta.  The  wild  pinks  also,  which 
straggle  about  here  and  there  in  the  lowlands,  sure  not  to 
escape  notice  among  the  many  visitors  constantly  flitting 
to  and  fro,  here  take  the  precaution  of  growing  larger 
blossoms,  besides  massing  themselves  together  in  such  a 
way  as  to  catch  the  eye  of  any  wandering  insect. 

Large  masses,  large  blossoms,  brilliant  colors — these 
are  the  means  by  which  the  fewer  insects  of  the  high  Alps 
are  guided  without  loss  of  time  to  the  place  where  they 
are  wanted;  and  flowers  which  might  never  be  found  out 
if  they  grew  separately  are  insured  against  neglect  by 
thus  growing  in  company. 

But  many  and  beautiful  as  are  the  moths  and  butter- 
flies of  the  mountains,  one  must  go  to  the  tropics  to  see 
them  in  their  full  glory  of  numbers,  size,  and  coloring. 

Of  all  parts  of  the  world,  South  America  is  richest  in 


198  The  Great  World's  Farm  | 

butterflies,  and  the  richest  part  of  South  America  is  the 
region  of  the  Amazons;  where,  also,  the  broad  belt  of 
forest  which  surrounds  the  land-surface  of  the  earth 
almost  continuously  at  the  equator  is  denser  than  any- 
where else,  and  swarms  with  insects  of  many  kinds. 

There  are  some  twelve  hundred  species  of  butterflies  in 
this  region;  but  these  gay  insects  do  not  care  for  the 
solemn  depths  of  the  forest,  where  they  find  little  or  no 
entertainment,  and  they  are  chiefly  to  be  seen  in  the  more 
or  less  open  paths,  where  there  is  more  light,  and  where, 
consequently,  more  flowers  are  to  be  found. 

Here  large  blue  butterflies,  and  many  others,  fly  along 
for  miles,  and  always  return  if  driven  into  the  forest.  For 
this  is  gloomy  and  even  musty,  like  a  cavern;  the  damp 
ground  is  not  covered  by  herbage,  there  is  little  beauty  or 
brilliancy  of  coloring  in  the  trees,  and  flowers  are  rare. 

The  fact  is  that,  according  to  the  German  proverb, 
"one  cannot  see  the  forest  for  the  trees."  They  are  so 
crowded  together,  and  they  run  up  to  such  a  height,  that 
there  is  little  to  be  seen  but  trunks,  canopied  by  a  mass  of 
foliage  so  dark  and  dense  that  the  sun  is  quite  powerless 
to  penetrate  it. 

Many  trees  never  blossom  until  they  are  a  hundred  feet 
high,  and  it  is  only  when  a  shower  of  bright  petals  falls 
from  above  that  there  is  any  sign  of  what  is  going  on 
overhead,  or  of  the  beauty,  displayed  to  insects  only,  out- 
side the  dark  canopy.  Beneath  it  the  world  is  dank,  dull, 
gloomy,  unrelieved  by  a  ray  of  light;  but  what  a  different 
world  it  is  above!  Here  the  sun  is  in  full  blaze,  and  bees 
in  swarms  are  humming  cheerily  over  the  magnificent  ban- 
quet of  flowers  spread  for  them. 

Bees  do  not  like  gloom,  or  even  the  checkered  shade 


Guests,  Welcome  and  Unwelcome        199 

which  contents  the  butterflies,  and  they  would  have  missed 
the  feast  if  the  flowers  had  grown  down  below. 

It  is  by  the  roadside,  on  the  margin  of  the  forest,  in 
the  paths,  and  along  the  river-banks  that  the  real  beauty 
of  tropical  vegetation  is  to  be  seen;  for  here  are  bushes, 
shrubs,  trees  of  every  height  adorned  with  festoons  of 
creepers,  and  brilliant  with  bright  flowers  and  gorgeous 
butterflies. 

Even  here,  however,  there  is  nothing  to  surpass  such 
masses  of  glorious  color  as  are  to  be  seen  on  our  heathery 
moors  or  gorse-covered  commons;  and  though  tropical 
blossoms  are  undoubtedly  splendid,  they  are  not  as  com- 
mon as  one  is  apt  to  fancy,  and  they  generally  last  but  a 
short  time,  beginning  to  fall  almost  at  once. 

Bees  abound  in  this  region,  but  they  keep  in  the  sun, 
among  the  blossoms  borne  high  up  overhead;  and  the 
butterflies  float  lazily  along  the  paths  which  are  checkered 
with  light  and  shade,  but  they  keep  for  the  most  part  near 
the  ground.  If  the  smaller  trees,  therefore,  followed  the 
example  of  the  giants  of  the  forest,  and  bore  their  blos- 
soms on  their  tops,  they  would  be  in  danger  of  missing 
both  classes  of  visitors.  The  bees  would  know  nothing 
about  them  down  in  the  shade,  and  the  butterflies  would 
not  rise  high  enough  to  find  them. 

Under  these  circumstances,  therefore,  many  trees,  such 
as  the  custard-apple,  bear  their  blossom  on  the  trunks  or 
larger  branches,  where  moths  and  butterflies  can  find  them. 
The  cacao  is  another  which  does  so,  and  when  the  large 
yellow  fruit  is  ripe,  the  trunks  of  some  of  the  smaller  trees 
are  hardly  to  be  seen,  so  thickly  does  it  cover  them. 

But  much  as  these  insects  do,  both  in  the  tropics  and 
in  the  mountains,  it  must  not  be  supposed  that  their  ser- 


200  The  Great  World's  Farm 

vices  could  be  dispensed  with  even  in  temperate  latitudes 
and  in  the  plains.  Quite  the  contrary.  Most  of  the 
European  orchids  are  fertilized  by  bees,  but  just  a  few 
species  cannot  get  on  without  the  help  of  moths.  There 
is  a  large  sphinx-moth  which  carries  pollen  to  and  from 
one  species  of  orchid  in  a  very  curious  way — on  its  eyes. 
The  pollen  of  this  flower  grows  in  tw^o  m.asses,  each 
perched  upon  a  stalk  which  passes  through  its  center,  and 
to  which  the  grains  are  united.  At  the  base  of  the  stalks 
are  tiny,  button-shaped  discs,  one  on  each  side  of  the 
stigma,  face  to  face.  When  the  moth  presses  its  head 
into  the  center  of  the  flower,  the  discs  come  into  contact 
with  its  eyes,  and  being  very  sticky,  they  adhere  so  firmly 
that  the  v/hole  thing  is  dragged  out — stalk,  pollen,  and 
all.  A  very  strange  object  one  of  these  moths  is  when  it 
is  thus  adorned,  for  the  stalks,  with  their  lumps  of  pollen 
at  the  end,  at  first  stand  out  straight,  like  horns  in  the 
wrong  place.  In  a  minute  or  so,  however,  they  contract 
and  bend  down,  and  then  the  pollen  is  in  exactly  the  right 
position  to  be  caught  and  held  by  the  stigma  of  the  next 
blossom  of  the  same  species,  which  the  insect  must,  one 
would  imagine,  be  in  haste  to  enter  if  it  knows  how  it  may 
get  rid  of  its  undesirable  appendages. 

Orchid-blossoms  remain  in  full  beauty  a  long  time, 
whether  cut  or  not,  as  long  as  they  are  not  fertilized;  but 
when  insects  are  allowed  to  get  at  them,  they  fade  rapidly 
and  go  to  seed. 

Among  the  flowers  specially  attractive  to  moths  in 
Europe  are  the  valerian,  petunia,  phlox,  hop,  nettle,  pink, 
ivy,  clematis,  pansy,  jessamine,  and  honeysuckle,  the  last 
being  frequented,  according  to  Gilbert  White,  by  a  large 
sphinx-moth,  which  appears  after  dusk,   and  feeds,   like 


Guests,  Welcome  and  Unwelcome        201 

the  humming-bird,  on  the  wing,  scarcely  ever  setthng,  and 
making  a  humming  noise  with  its  wmgs. 

The  jessamine  is  probably  fertilized  by  the  hawk-moth, 
which  hovers  in  like  manner;  but  jessamine-seed  is  rare  in 
England,  for  hawk-moths  are  rare,  too.  But  the  want  of 
hawk-moths  may  not  be  the  sole  reason  for  the  scarcity 
of  seed.  The  humble-bees  are  also  in  some  measure  to 
blame,  for  they  come  to  the  blossoms  in  search  of  nectar, 
and  finding  no  perch  upon  which  they  can  stand  to  suck 
in  the  proper  way — the  only  way  to  benefit  the  flower — 
they  get  what  they  want  by  gnawing  through  the  tube  of 
the  corolla,  which  soon  drops  in  consequence. 

Flowers  which  open  at  night  are  of  course  especially 
dependent  upon  night-flying  moths;  and  as  colors  would 
not  be  seen,  they  are  generally  white  or  pale  yellow,  and 
have  no  lines  to  show  where  the  nectar  is,  for  these  also 
would  not  be  visible;  but  they  are  often  so  sweet  as  to  be 
scented  from  afar.  The  large  white  bindweed,  though 
it  opens  by  day,  remains  open  at  night,  when  the 
moon  shines,  but  not  otherwise,  to  receive  the  visits  of 
moths. 

Wherever,  in  any  part  of  the  world,  there  is  a  dearth 
of  bright-colored  flowers,  there,  as  a  rule,  is  a  scarcity 
of  insects,  and  vice  versa,  for  where  insects  are  wanting, 
there  the  flowers  fertilized  by  them  cannot  of  course 
flourish. 

The  scarcity  of  both  these  is  very  conspicuous  in  the 
Galapagos  Islands,  situated  on  the  equator,  some  seven 
hundred  miles  west  of  South  America.  In  Juan  Fernan- 
dez also,  which  lies  about  four  hundred  miles  off  Chili, 
ferns  form  the  larger  part  of  the  vegetation,  as  they  do  in 
most  of   the  South   Sea  Islands.     But  there  is  no  such 


202  The  Great  World's  Farm 

total  absence  of  showy  blossoms  in  Juan  Fernandez  as  in 
the  Galapagos.  One  shrub  which  flourishes  there  bears 
snowy  blossoms,  like  those  of  the  magnolia;  another,  also 
plentiful,  has  dark  blue  flowers;  and  besides  these,  there 
are  large  patches  of  a  white,  lily-like  bulb,  and  there  are 
two  conspicuous  yellow  flowers  as  well. 

Yet  Juan  Fernandez  is  poor  in  insects.  It  has  but  one 
butterfly,  and  that  is  rare;  there  are  only  four  species  of 
moths,  and  no  bees  at  all,  but  some  which  are  very  minute, 
and  of  no  more  use  to  large  blossoms  than  the  flies,  of 
which  there  are  twenty  species. 

But  the  poverty  of  the  insect-life  is  made  up  for  by  the 
presence  of  humming-birds,  which  are  so  abundant  that 
there  are  one  or  two  in  every  shrub ;  and  these  when  killed 
are  usually  found  with  the  front  of  their  heads  covered 
with  pollen. 

The  group  of  honey-eating  birds  is  so  immense,  both 
in  the  islands  of  the  Pacific,  Australia,  America — North 
and  South — the  Moluccas,  etc.,  that  there  can  be  no  doubt 
as  to  the  large  share  they  take  in  conveying  pollen  from 
one  flower  to  another. 

The  ruby-throated  humming-bird  frequents  lilacs, 
phloxes,  portulaccas,  morningglories,  roses,  honeysuckles, 
snap-dragons,  fuchsias,  and  many  other  flowers;  and  in 
dry  weather,  before  the  spring  begins,  it  will  even  enter 
greenhouses  and  suck  the  fuchsias  there,  which  it  does 
more  rapidly  than  the  honey-bee. 

The  Portuguese  name  for  the  humming-bird  is  Beija 
Flor,  *' Kiss-flower";  but  the  little  creature  is  not  so 
ethereal  in  its  habits  as  its  appearance  and  poetical  name 
have  led  people  to  suppose.  It  does  **kiss"  the  flowers, 
but  with  a  view  to  something  more  substantial  than  nectar 


Guests,  Welcome  and  Unwelcome        203 

merely,  though  that  may  be  all  very  well  as  an  addition  to 
its  food. 

Many  a  humming-bird  has  been  starved  to  death  in 
captivity,  owing  to  the  mistaken  notion  that  honey,  or 
sugar-and-water,  was  all  that  it  needed;  whereas  these 
living,  flashing  jewels  possess  tongues  which  are  exactly 
adapted  for  picking  up  insects;  and  insects  are  their  prin- 
cipal food,  though  they  take  nectar  as  well. 

The  humming-bird's  tongue  is  long,  and  can  be 
stretched  out  far  beyond  its  bill;  it  is  very  flexible,  and 
being  cleft  in  two  it  can  be  opened  and  shut  at  will,  "like 
a  delicate,  pliable  pair  of  forceps." 

The  humming-bird  is,  indeed,  nearly  related  to  the 
swift,  and  its  chief  diet  consists  of  the  small  insects,  which 
are  seldom  wanting  in  the  long-throated  blossoms  of  the 
tropics.  The  sheaths  of  the  arums  and  their  kindred  are 
generally  full  of  insects,  too;  so  are  those  of  the  palms, 
and  the  ** pitchers"  with  which  many  plants  are  furnished 
likewise  afford  insects  in  abundance. 

Whether  the  birds  go  for  nectar  or  for  insects,  it  is  all 
the  same  so  far  as  the  plant  is  concerned,  for  in  neither 
case  can  they  help  coming  in  contact  with  the  stamens  and 
getting  their  heads  and  beaks  dusted  with  pollen. 

Bees,  butterflies,  moths,  birds — these  are  the  most 
conspicuous  of  the  "under-gardeners"  to  whom  is  in- 
trusted the  important  work  of  fertilization;  but  there  are 
others  equally  useful  in  their  way,  though  their  sphere  of 
operations  is  less  extensive.  Even  the  wasps  do  some- 
thing, for  in  the  absence  of  fruit  they  suck  flowers,  as 
Gilbert  White  remarked,  especially  those  of  the  ivy  and 
small  umbelliferous  flowers;  they  are  especially  attracted 
by   the   red   and  yellow  blossoms   of  the   "poker-plant" 


I 
204  The  Great  World's  Farm  ^ 

(Tritoma),  which  blossoms  in  the  late  summer,  and  may 
be  seen  creeping  quite  into  the  tubes;  and  they  are  also 
said  to  fertilize  the  dahlia,  which  is  shunned  by  bees. 

''Where  the  bee  sucks  honey  the  wasp  sucks  poison," 
is  a  common  saying,  and  as  devoid  of  foundation  as  such 
sayings  often  are.  It  is  a  libel  on  the  w^asp,  and  too 
flattering  for  the  bee;  for  if  the  bee  does  suck  and  store 
honey,  which  last  the  wasp  does  not  pretend  to  do,  it  also 
secretes  poison,  and  its  sting  is  generally  considered  much 
the  worse  of  the  two. 

To  small,  flat  flowers,  whose  nectar  hes  so  near  the  sur- 
face as  to  require  little  probing  for,  beetles  and  small  flies 
are  almost  as  useful  as  bees,  and  may  be  seen  in  crowds 
on  such  little  blossoms  as  those  of  the  wild  carrot,  and 
others  of  the  same  family  which  grow  together  in  flat 
heads  or  umbels.  Even  the  water-side  midges  do  their 
part  among  the  small  flowers  of  the  river  banks. 

All  sorts  of  little  flies,  gnats,  and  midges  are  attracted 
also  to  the  arums,  some  by  the  prospect  of  pollen  and 
nectar,  others,  as  the  carrion-flies,  by  the  flesh-like  ap- 
pearance and  smell  of  many  foreign  species,  on  which 
they  even  lay  their  eggs,  supposing  that  their  grubs  will 
be  well  fed;  another  illustration  of  what  was  said  before, 
that  if  they  existed  solely  for  the  purpose  of  attracting 
insects,  all  flower  scents  might  just  as  well  be  what  human 
beings  consider  disagreeable. 

The  arrangements  of  the  arum  family  are  so  curious 
as  to  be  worth  a  little  special  attention.  We  most  of  us 
know  the  so-called  "arum-lily,"  with  its  white  flower  with 
the  golden  scepter.  The  flowers  of  the  arum  are  con- 
tained in  a  sheath,  properly  called  a  spathe,  which  is 
snowy  white   in  the  "arum-lily"  and  greenish  in  the  wild 


Guests,  Welcome  and  Unwelcome        205 

one.  The  real  blossoms  are  clustered  round  the  scepter, 
or  spadix,  which  is  golden  in  the  one,  and  purplish,  or 
brown,  in  the  other. 

In  some  of  the  southern  and  foreign  arums  the  lower 
part  of  the  sheath,  which  is  enlarged  and  contains  the 
blossoms,  is  shut  off  by  a  ring  of  longish  hairs  which  point 
downwards  and  allow  the  visitors  to  enter  easily,  but 
effectually  prevent  their  coming  out  again  until  they  have 
done  what  is  wanted  of  them.  The  lower  part  of  the 
spadix  generally  bears  the  flowers  with  pistils,  those  with 
stamens  being  arranged  in  a  ring  a  little  above.  The 
lower  blossoms  are  ready  first,  and  to  them  the  insects,  or 
some  of  them,  bring  pollen  from  other  flowers  of  the  same 
species.  But  it  is  not  enough  for  them  to  bring  pollen, 
they  must  also  carry  some  away,  and  for  this  purpose  they 
must  be  kept  until  the  anthers  burst. 

Meanwhile  their  prison  is  made  very  comfortable  for 
them;  it  is  pleasantly  scented — we  are  not  speaking  now 
of  the  fleshy  species — it  is  also  warmed  and  provided  with 
nectar.  When  the  anthers  burst,  pollen  is  added  to  the 
feast,  and  some  of  the  captives  devour  it  so  greedily  as  to 
be  quite  intoxicated.  Enough,  however,  remains  adher- 
ing to  their  legs  and  bodies  to  make  them  acceptable  visi- 
tors elsewhere,  and  as  soon  as  the  pollen  is  shed,  and 
there  is  no  further  reason  for  keeping  them,  the  hairs 
which  prevented  their  escape  wither  and  die,  and  they  are 
free  to  depart — generally,  but  not  always.  The  hairy 
arum  of  the  South  is  said  to  show  her  gratitude  for  the 
services  rendered  to  her  by  her  visitors,  carrion-flies,  in  a 
remarkable  manner.  She  catches  and  devours  many, 
digesting  them  by  means  of  the  sticky  hairs  which  cover 
the  inside  of  the  sheath. 


2o6  The  Great  World's  Farm 

Most  of  the  arums  of  the  temperate  zones  blossom 
early  in  the  year,  when  the  nights  are  still  chilly  enough 
to  make  the  prospect  of  a  warm  lodging  attractive. 

Blossoms  breathe  more  rapidly  than  leaves,  and  are 
always  therefore  a  little  the  warmer.  Buds  just  opening 
breathe  so  fast,  if  they  are  large,  like  those  of  a  cucumber, 
that  when  they  are  isolated  under  a  glass  containing  a  tiny 
thermometer,  the  mercury  may  be  seen  to  rise  sometimes 
nearly  two  degrees. 

Many  blossoms  heat  so  much  more  than  this,  however, 
that  the  difference  may  be  felt  as  well  as  seen.  This  is 
the  case  with  the  arums,  whose  so-called  blossom  is  really 
an  assemblage  of  many  blossoms.  In  the  common  wild 
arum,  "lords  and  ladies,"  the  temperature  rises  several 
degrees,  but  in  the  heart-leaved  arum  of  the  Isle  of  Bour- 
bon the  temperature  of  the  sceptre,  or  spadix,  has  been 
known  to  rise  to  95^  F.,  and  nearly  102°  F.,  and  that, 
too,  when  the  temperature  of  the  air  was  only  59 ""  F. 

But  the  common  Italian  arum  outdoes  even  its  tropical 
cousin,  and  its  spadix  becomes  hotter  than  a  hot  bath,  its 
temperature  being  nearly  lio'  F. 

Arums  are  especially  marsh-plants,  and  though  one 
does  not  naturally  associate  the  idea  of  warmth  with  such 
cold  creatures  as  snails,  it  seems  that  it  is  these  which  are 
chiefly  attracted  to  the  arums  of  south  Europe,  and  no 
doubt,  of  other  parts  of  the  world. 

One  of  the  foreign  arums  grown  in  hot-houses  for  the 
sake  of  their  handsome  foliage  was  observed  one  day  at 
noon  to  begin  to  blossom  and  grow  warm  at  the  same  time, 
its  temperature  rising  beyond  100°  F.  Suddenly  it  gave 
out  a  strong,  fragrant  scent,  between  that  of  cinnamon  and 
musk,  which  filled  the  whole  house,  and  would  no  doubt 


Guests,  Welcome  and  Unwelcome        207 

have  been  a  well-understood  signal  in  its  own  country, 
telling  the  small  marsh-snails  that  their  night  quarters  were 
ready.  These  would  dimb  the  stalk  and  find  entrance  by 
a  narrow  opening  at  the  base  of  the  sheath,  which  would 
soon  after  close  upon  them.  Twenty-four  hours  later  the 
scent  and  warmth  have  much  diminished,  but  then  the 
anthers  open  and  drop  down  their  pollen,  not  in  separate 
grains,  but  in  chains  or  tassels  of  grains  adhering  together, 
as  much  as  an  inch  long,  and  far  too  bulky  therefore  to  be 
carried  away  by  insects.  On  coming  in  contact  with  the 
moist  bodies  of  the  snails,  however,  the  chains  separate 
into  grains,  which  adhere  and  are  borne  away  when  the 
guests  move  on. 

And  they  are  obliged  to  move  on  soon  after  the  pollen 
has  fallen  or  else  they  would  be  suffocated;  for  the  blos- 
soms have  been  breathing  vigorously  in  a  confined  space, 
and  so  much  carbon  has  been  burned,  and  so  much  carbon 
dioxide  produced,  that  the  bulb  of  the  sheath  is  completely 
filled  with  it,  and  a  glowing  match  held  within  is  extin- 
guished. Such  visitors  as  stay  too  long  are  therefore 
safely  suffocated,  and  thus  prevented  from  eating  the 
young  fruit,  which  they  would  otherwise  do  without  fail. 

The  prudent  snails,  however,  having  enjoyed  their 
warm  bed  and  nectar,  do  not  outstay  their  welcome;  but 
when  these  passing  pleasures  have  come  to  an  end,  they 
linger  no  longer,  make  the  best  of  their  way  up  the  sheath 
and  down  the  long  stem,  and  then  proceed  without  delay 
to  climb  some  other  plant  whose  blossoms  are  beginning 
to  give  fragrant  notice  that  another  pleasant  guest-chamber 
is  ready  for  their  reception.  Thanks  to  this  diHgcnce, 
therefore,  pollen  is  brought  to  the  pistils,  as  soon  as  they 
are  ready  for  it,  by  the  ** fastest  snail-express." 


2o8  The  Great  World's  Farm 

Hitherto  we  have  confined  our  attention  to  the  welcome 
guests;  but  there  are  unwelcome  ones  also,  and  the  very 
snails  last  considered  have  two  sides  to  their  character. 
Indeed,  the  beneficent  side  is  not  the  one  with  which  we 
are  familiar,  being  rather  a  recent  discovery,  while  their 
mischievous  propensities  are  well  and  widely  known. 
Even  the  arums  which  welcome  them  as  pollen-carriers 
need  some  sort  of  protection  against  them.  They  have 
to  be  tempted  to  undertake  what  to  them  is  really  an 
immense  journey,  by  special  attractions,  otherwise,  being- 
voracious  eaters,  they  would  simply  begin  to  devour  the 
first  leaf  they  came  across.  Then,  when  they  have  started, 
all  loitering  by  the  way  is  sternly  discouraged,  for  arum- 
leaves  are  acid,  and  even  poisonous;  so  there  is  no  temp- 
tation to  make  a  meal  of  them. 

Useful  as  they  are  to  arums  and  arum-like  plants,  they 
are  not  generally  desirable  as  visitors,  and  are  not  often 
found  in  flowers,  bristles  and  prickles  being  enough  to 
turn  them  back  at  once.  No  wingless  visitors  are  gen- 
erally welcome,  for  they  crawl  slowly,  lose  pollen  by  the 
way,  by  getting  it  rubbed  off  them,  and  are  usually  so 
indiscriminate  in  their  tastes  that  they  go  as  readily  to 
one  blossom  as  another,  and  it  is  quite  a  chance  what 
pollen,  if  any,  they  may  bring  with  them. 

It  is,  of  course,  not  to  the  plant's  interest  that  its 
pollen  and  nectar  should  be  taken  by  insects  which  plunder 
without  making  payment  in  return,  as  it  is  thereby  robbed 
of  its  means  of  attracting  other  and  more  useful  insects. 
But  the  useless  ones  are  just  as  fond  of  nectar  as  the  use- 
ful, just  as  quick,  too,  to  find  it  out,  wherever  it  may  be 
hidden,  so  that  many  devices  are  needed  to  baffle  these 
unwelcome  guests. 


Guests,  Welcome  and  Unwelcome        209 

Human  beings  can,  it  is  said,  detect  less  than  the 
twenty-millionth  part  of  a  grain  of  musk;  but  in  keenness 
of  scent  they  are  far  surpassed  by  the  insect  world. 

Where  is  the  man  who  can  detect  any  difference,  by 
smell  or  otherwise,  between  cane-sugar  and  beet-sugar, 
when  the  latter  is  properly  refined? — not,  of  course,  such 
as  one  meets  with  in  continental  hotels.  Yet  the  bees 
know  well,  for  if  the  choice  be  given  them,  they  will  take 
the  cane  and  leave  the  beet. 

And  ants  are  not  only>  as  fond  of  sweets  as  bees,  but 
will  find  them  out  from  an  immense  distance.  They  have 
been  known  to  make  their  way  up  from  the  garden  to  the 
second  story  of  a  house,  by  means  of  an  outside  bell-wire, 
all  for  the  sake  of  some  dried  fruit  which  they  had  scented 
out.  They  are  sure,  therefore,  to  know  where  nectar  may 
be  had,  as  well  as  the  bees  themselves;  and  yet,  what 
with  their  crawling,  and  their  tidy  habit  of  constantly 
cleaning  themselves,  and  their  hard  coats,  which  are  not 
suited  for  carrying  pollen,  they  are  some  of  the  least  wel- 
come guests  that  a  flower  can  have. 

When  the  ants  do  get  a  chance,  they  make  the  most  of 
it,  and  swarm  in  greedily;  but  on  the  whole  they  are  pretty 
well  kept  out,  now  by  one  means,  now  by  another. 

The  snap-dragon,  for  instance,  keeps  her  mouth  so 
firmly  closed  that  none  but  the  strong  humble-bee  can 
force  its  way  in,  until,  that  is,  the  necessary  pollen  has 
been  brought.  But  then,  when  the  seed  is  made  sure,  and 
the  ants  can  do  no  harm,  the  lips  are  unclosed,  and  they 
are  generously  admitted  to  what  remains  of  the  feast,  an 
opportunity  of  which  they  do  not  fail  to  make  use. 

Ants,  like  other  wingless  insects,  prefer  to  avoid  the 
dew,    and   so   are   not   astir   very   early.      Some    flowers. 


OTO  The  Great  World's  Farm 

therefore,  unfold  for  only  a  short  time  during  the  first 
hours  of  the  morning  and  close  again  by  9  a.  m.;  and  in 
all  probabihty  there  is  a  close  connection  between  the 
times  when  flowers  open  and  close,  and  the  hours  when 
their  friends  and  enemies  are  abroad. 

Plants  such  as  the  teasel  keep  off  the  ants  by  means  of 
the  basins  formed  by  their  leaves,  which  catch  the  dew  as 
it  trickles  down  their  stems,  and  keep  it  so  effectually  as 
to  be  seldom  empty  while  the  plant  is  in  blossom.  Water 
is  completely  bafiling  to  ants,  and  if  placed  on  the  stem  of 
a  plant  thus  protected,  they  run  helplessly  up  and  down, 
and  then  drop  to  the  ground. 

Stickiness,  too,  of  all  kinds,  is  their  abhorrence,  and 
is  often  fatal  to  them,  whether  in  the  form  of  sticky  hairs 
or  sticky  juice.  The  lettuce  is  one  of  many  plants  fur- 
nished with  a  milky  juice  which  is  especially  abundant 
near  the  flowers.  If  an  ant  crawls  up  the  stem,  its  hooked 
feet  are  so  sharp  as  to  cut  through  the  outer  skin,  and  the 
juice  which  at  once  oozes  out  hardens  rapidly,  gluing  it  to 
the  spot,  while  the  little  creature's  frantic  efforts  to  clean 
itself  only  make  matters  worse,  and  it  seldom  succeeds  in 
escaping. 

Many  of  the  plants  belonging  to  the  order  which  con- 
tains the  catch-flies,  campions  and  pinks,  are  provided 
with  rings  of  sticky  hairs,  and  as  many  as  sixty-four  small 
insects  have  been  found  at  once  on  one  flower-stalk  of  the 
red  German  catch-fly.  One  can  imagine  how  little  nectar 
would  have  been  left  to  attract  profitable  insects  if  these 
sixty-four  had  been  allowed  to  have  their  way.  Ants  are 
usually  very  wary  in  their  manner  of  proceeding,  and  feel 
their  way  carefully  up  the  stalk  until  they  reach  the  sticky 
ring,  whereupon  they  generally  turn  round  and  come  down 


Guests,  Welcome  and  Unwelcome        211 

again;  but  if  they  do  venture  to  proceed  they  are  surely 
lost. 

Stickiness  is  no  impediment  to  slugs  and  snails,  how- 
ever, for  they  overcome  it  by  covering  it  with  their  own 
slime.  What  they  do  mind  are  bristles  and  prickles, 
which  the  armor-clad  ant  can  afford  to  despise. 

Pricklets,  hairs,  and  fringes  inside  the  blossom,  serve 
often  a  double  purpose,  for  they  both  keep  out  unwelcome 
visitors  and  make  the  welcome  ones  reach  the  nectar  by 
the  right  way.  Thus  insects  wanting  to  get  at  the  honey 
in  the  spur  of  the  garden-nasturtium  are  obliged  to  climb 
over  the  fringe  on  one  of  its  three  lower  petals,  and  this 
they  cannot  do  without  coming  in  contact  with  anthers  or 
pistils,  which  they  might  otherwise  pass  untouched. 

Plants  sometimes  need  protection  against  even  their 
best  friends,  the  bees,  for  some  of  these,  in  spite  of  their 
many  good  qualities,  have  a  way  of  trying  to  reach  the 
nectar  by  other  than  the  right  way — by  house-breaking, 
in  fact,  instead  of  by  the  front  door;  and  others,  though 
willing  enough  to  come  in  properly,  are  too  small  to  be 
serviceable  to  large  blossoms.  We  have  already  men- 
tioned how  humble-bees  bite  through  the  tube  of  the  jessa- 
mine, because  they  find  nothing  to  stand  upon  while  they 
suck  the  blossom.  But  as  the  jessamine  is  a  foreign 
flower,  this  may  be  thought  excusable  enough,  as  there 
are  few  insects  here  able  to  reach  the  nectar  in  the  right 
way. 

Some  bees,  however,  really  seem  to  be  lazily  inclined, 
for  to  save  time  and  trouble,  they  always  bite  a  hole  in 
the  columbine  and  certain  other  blossoms. 

The  bladder-campion,  however,  successfully  frustrates 
any  such  designs  by  growing  a  calyx  which  is  so  inflated 


212  The  Great  .World's  Farm 

that  no  bee's  proboscis  is  long  enough  to  reach  the  nectar 
by  means  of  a  hole  made  in  it.  Others  have  calyxes  so 
hard  and  tough  that  even  humble-bees  and  ants  are  baffled 
by  them. 

But  then,  the  little  bees — where  big  bees  can  enter, 
why  not  little  ones?  The  foxglove,  for  instance,  gapes 
widely  open;  and  as  stamens  and  pistil  lie  close  under  the 
upper  side  of  the  blossom  they  are  quite  out  of  the  way 
of  the  small  bee,  which  would  pass  in  and  out  without 
touching  them  if  it  were  allowed  to  find  entrance  at  all. 
But  an  observer  who  watched  the  flowers  carefully 
throughout  a  season  in  North  Wales,  where  they  espe- 
cially abound,  saw  many  small  bees  make  the  attempt  but 
only  one  succeed.  It  looks  easy  enough,  but  the  upper 
part  of  the  blossom  is  so  smooth  as  to  be  actually  slip- 
pery, and  affords  no  foothold;  and  the  lower  part  is  beset 
with  stiff  hairs,  which  are  very  embarrassing  to  smaller 
insects,  though  the  humble-bee  uses  them  as  rests  for 
her  feet,  and  clings  to  them  while  she  sucks. 

It  is  interesting  to  watch  the  methodical  way  in  which 
a  humble-bee  visits  and  explores  a  spire  of  foxglove, 
always  beginning  with  the  low^est  bell  and  working  upwards; 
but  it  may  not  have  occurred  to  all  of  us  that  if  she 
reversed  her  operations  the  foxglove's  hope  of  cross-fer- 
tilization would  be  gone.  So  it  is,  however,  for  the  fox- 
glove-blossoms not  only  open  gradually,  beginning  with 
the  lowermost,  but  the  pollen  is  ripe  before  the  pistils  are 
ready  for  it;  and  consequently  the  pistils  of  the  lower 
blossoms  are  waiting  for  pollen — their  own  being  safely 
gone — while  the  anthers  of  the  upper  blossoms  are  dis- 
charging it.  If  the  bee  began  at  the  top,  she  would  only 
bring  to  the  pistils  pollen  from  the  upper  blossoms  on  the 


Guests,  Welcome  and  Unwelcome        213 

same  stalk;  whereas,  leaving  off  at  the  top,  she  carries 
pollen  away  to  the  lowest  blossoms  on  the  stem  of  another 
plant. 

Such  are  a  few,  and  only  a  few,  of  the  many  marvellous 
provisions  for  insuring  fertilization,  for  preventing  self- 
fertilization,  for  promoting  cross-fertilization,  and  for 
preventing  the  robbery  of  pollen  and  nectar  by  insects 
which  would  not  benefit  the  plant;  and  to  conclude  with 
the  words  of  Professor  Asa  Gray : 

"If  these  structures  and  their  operations  do  not  argue 
intention,  what  stronger  evidence  of  intention  in  nature 
can  there  possibly  be?  If  they  do,  such  evidences  are 
countless,  and  almost  every  blossom  brings  distinct  testi- 
mony to  the  existence  and  providence  of  a  designer  and 
ordainer,  without  whom,  we  may  well  believe,  not  merely 
a  sparrow,  not  even  a  grain  of  pollen,  may  fall." 

QUESTIONS  FOR  REVIEW 

1.  What  peculiarities  have  Alpine  flowers  and  why? 

2.  How  do  the  different  classes  of  tropical  flowers  secure 
their  insect  visitors? 

3.  How  does  the  sphinx-moth  fertilize  orchids? 

4.  What  peculiarity  has  the  bind-weed? 

5.  In  what  islands  is  the  lack  of  insect  life  made  good  by 
humming-birds? 

6.  What  is  the  humming-bird's  food,  and  how  does  he  get  it? 

7.  Describe  the  peculiar  habits  of  the  arum. 

8.  Why  are  ants  and  snails  usually  unwelcome  visitors? 

9.  By  what  means  do  flowers  keep  off  their  enemies? 

10.  Why  is  the  bee's  method  of  visiting  the  foxglove 
especially  efficacious. 


CHAPTER  XVII 

SEED-SCATTERING 

The  great  end  of  a  plant's  life  is  to  bear  fruit.  It  is 
for  this  that  roots  and  leaves  collect  nourishment,  and 
that  insects  and  birds  are  attracted  to  the  blossoms  by 
bright  colors  and  the  prospect  of  food.  So  entirely, 
indeed,  is  fruit-bearing  the  aim  of  the  plant's  life,  that 
many  plants  are  dry  and  withered  by  the  time  the  fruit  is 
ripe,  having  given  up  all  their  sap,  their  very  Hfe,  to  bring 
it  to  perfection.  In  any  case,  whether  it  last  for  one  year, 
or  two,  or  many,  the  plant's  life  is  devoted  to  making 
preparation  for  its  offspring. 

For  this  reason  few  wild  flowers  are  double,  as  the 
number  of  petals  must  be  increased  at  the  expense  of 
stamens  and  pistils,  and  without  these  fruit  is  impossible. 

A  cherry-tree  covered  with  double  blossoms  may  be 
very  ornamental,  but  the  gardener  grows  it  for  its  blos- 
soms only,  and  does  not  expect  fruit  from  it.  When  his 
object  is  fruit,  however,  he  sometimes  interferes  in  another 
way,  which  has  the  same  result,  so  far  as  the  plant  is  con- 
cerned; for  he  increases  the  eatable  part  of  the  fruit,  in 
some  cases,  as  he  increases  the  number  of  the  petals — at 
the  expense  of  the  seed. 

A  plant's  fruit  is  the  ripened  ovary,  containing  the 
seed;  and  when  the  seed  is  the  part  used  for  food,  man 
naturally  devotes  his  attention  to  that,  and  cares  nothing 
for  the  case.     From  corn,  for  example,  and  from  nuts,  he 

214 


11 


Seed-Scattering  215 

wants  the  seed,  not  the  husk  or  shell,  and  therefore  he 
cultivates  and  increases  the  size  of  the  seeds.  But  the 
seeds  of  pears,  grapes,  pine-apples,  oranges,  dates,  are 
not  what  he  wants;  and  in  some  of  the  best  sorts  of  all 
these  he  has  so  cultivated  the  ovary  or  fleshy  envelope, 
at  the  expense  of  the  seeds,  that  these  have  almost,  if  not 
quite,  disappeared. 

But  even  when  the  plant  is  left  in  a  state  of  nature, 
and  allowed  to  produce  seed  in  abundance,  it  often  needs 
further  help,  if  its  progeny  are  to  grow  up  healthy,  and 
vigorous  enough  to  hold  their  own  among  their  many 
competitors.     The  seed  must  be  scattered. 

The  gardener  often  finds  it  advisable  to  get  his  seed 
from  some  little  distance,  the  plants  raised  from  it  being 
distinctly  better  than  those  grown  from  seed  ripened  in  the 
same  place.  This  is  one  reason  why  it  is  for  the  plant's 
good  that  its  seed  should  be  scattered;  and  here,  of 
course,  we  mean  by  the  "plant"  the  race,  and  not  the 
individual.      But  there  are  many  other  reasons. 

If  seeds  are  dropped  close  round  the  parent-plant,  in  a 
confined  space,  they  grow  up  in  a  crowd,  and  there  is  a 
desperate  struggle  for  existence.  Being  all  of  the  same 
species,  they  all  want  the  same  kinds  of  food,  and  none 
have  much  advantage  over  the  rest.  A  few  seeds  may 
have  been  a  trifle  larger,  and  may  produce  seedlings  a 
trifle  stronger,  and  better  able  to  battle  for  what  they 
want,  but  the  difference  is  usually  slight,  and  the  chances 
are  that  all  will  grow  up  weakly. 

Where  seedlings  are  crowded  together  there  must 
always  be  a  struggle  as  to  which  shall  survive,  but  it  is 
much  more  severe  where  all  are  of  the  same  sort.  Where 
they  are  mixed,  some  will  have  advantages.     They  may 


21 6  The  Great  World's  Farm 

be  larger  and  stronger,  or  they  may  be  better  fitted  for  the 
soil  and  situation.  Whatever  the  advantage  may  be, 
those  possessing  it  will  speedily  overpower  their  less  for- 
tunate rivals,  and  then,  having  secured  sufficient  elbow- 
room,  will  grow  up  strong  and  healthy. 

Plants  of  different  species,  when  crowded  together,  are 
better  off  in  another  respect,  for  they  do  not  all  want  pre- 
cisely the  same  amount  of  the  various  mineral  foods,  and 
so  there  is  more  for  all.  For  this  reason  it  is  a  very 
usual  thing  to  sow  a  grass-field  with  seed  of  different 
species;  and  the  greater  the  variety,  the  heavier  the  crop 
of  hay,  because  the  plants  have  had  a  better  opportunity 
of  obtaining  food. 

On  this  account,  therefore,  as  well  as  that  they  may 
have  change  of  air,  it  is  well  for  seeds  that  they  should  be 
scattered,  or  otherwise  dispersed.  But  there  are  other 
reasons  still. 

Some  plants  need  shelter,  and  are  killed  by  sudden 
exposure.  If  they  had  no  means  of  dispersing  their  seeds, 
not  only  they,  the  parents,  but  their  whole  progeny,  might 
be  exterminated,  by  the  removal  of  trees,  etc.  Or  again, 
by  the  draining  of  a  pond,  or  drying  up  of  a  brook,  plants 
needing  much  moisture  might  be  killed  out  of  a  neighbor- 
hood, if  all  their  seeds  dropped  close  round  them,  while 
they  might  continue  to  flourish  if  they  were  able  to  migrate 
the  distance  of  only  a  few  yards. 

In  some  cases,  too,  the  parent  so  exhausts  the  soil, 
that  the  children  have  no  chance  of  thriving,  if  they  grow 
under  its  shadow;  and  then  again,  if  cross-fertilization  be 
an  advantage  to  the  plant,  even  where  not  absolutely 
essential,  it  certainly  seems — from  experiments  made  in 
crossing  Indian-corn  and  beans  with  plants  grown  some 


Seed-Scattering  217 

miles  away — that  cross-fertilization  with  plants  at  a  dis- 
tance is  more  beneficial  still,  the  produce  being  in  each 
case  very  greatly  augmented. 

Such,  then,  are  the  strong  arguments  in  favor  of 
Nature's  plan  of  scattering  her  seed  far  and  wide:  the 
plants  gain  change  of  air  and  change  of  soil;  competition 
is  less  keen,  cross-fertilization  is  promoted;  and  when 
driven  by  stress  of  circumstances  from  one  neighborhood, 
they  are  able  to  gain  a  settlement  in  another. 

Winds,  waves,  birds,  beasts,  fishes,  and  even  man  him- 
self, are  all  pressed  into  the  plant's  service,  and  made  to 
act  as  seed-carriers.  But  in  some  cases  the  plant  itself 
acts,  and  acts  alone,  sending  her  seeds  to  quite  consider- 
able distances. 

Many  years  ago,  there  was  a  certain  bare,  rocky  craig 
near  Dunkeld,  which  the  Duke  of  Athole  desired  to  have 
planted  with  trees,  though  he  was  quite  at  a  loss  how  to 
accomplish  it.  For  as  the  place  was  simply  inaccessible, 
no  one  could  chmb  up,  either  to  sow  seeds  or  to  plant 
saplings.  The  Duke  mentioned  his  difficulty  to  Nasmyth, 
and  he,  noticing  a  pair  of  small  cannon  in  front  of  the 
castle,  ordered  a  number  of  tin  canisters,  filled  them  with 
suitable  seeds,  and  fired  them  from  the  guns  up  the  high 
face  of  the  crag,  where  they  burst,  and  scattered  their 
contents  in  all  directions.  Some  few  years  later  there 
were  trees  flourishing  luxuriantly  in  all  the  recesses  of  the 
cHff. 

Plants  cannot  perhaps  shoot  their  seeds  quite  so  eftec- 
tually  as  this,  but  in  many  the  seed-vessels  split  with  so 
much  of  an  explosion  that  the  seeds  are  discharged  to  dis- 
tances which,  at  all  events,  remove  them  from  the  danger 
of  being  squeezed  to  death  in  a  crowd.     The  touch-me-not 


2 1 8  The  Great  World's  Farm 

balsam  is  one  of  these.  But  the  sand-box  tree  of  Barba- 
does  is  much  more  energetic.  Its  fruit  is  rather  Hke  a 
small  melon  in  shape,  but  hard  and  woody,  and  when  ripe 
it  bursts  with  a  loud  report.  One  of  these — dried  very 
gradually  in  the  hope  of  its  remaining  intact — exploded 
nine  months  after  it  was  gathered,  and  so  violently  as  to 
break  the  wooden  box  in  which  it  was  kept  quite  to  pieces. 
The  seeds  were  scattered  in  all  directions,  but  would  of 
course  have  been  carried  very  much  further  had  they  been 
unconfined. 

The  fruit  of  the  squirting  cucumber  has  to  be  bound 
round  with  copper-wire  when  ripe,  to  prevent  its  shooting 
out  its  seeds. 

The  pods  of  the  Chinese  wistaria  also  explode  with  a 
sharp,  loud  report,  and  the  seeds  may  be  carried  at  least 
thirty  feet;  while  those  of  the  American  witch-hazel  are 
shot  out  to  a  distance  of  from  twenty  to  five-and-forty 
feet.  If,  when  these  and  other  similar  seeds  are  dis- 
charged, a  strong  wind  should  happen  to  be  blowing,  they 
may  of  course  be  carried  much  further. 

Even  individual  seeds  transported  by  the  wind  do  not 
always  accomplish  the  whole  of  their  journey  **all  in  a 
breath";  for  the  wind  comes  in  successive  waves,  not  in 
one  continuous  blast. 

Of  course,  the  lighter  the  seeds,  the  better  chance  they 
have  of  being  carried  far,  unless  they  are  caught  in  these 
ways;  and  some  few  seeds,  such  as  those  of  the  orchids, 
are  so  exceedingly  minute  and  light,  that  no  mere  lull  in 
the  wind  is  enough  to  make  them  drop,  for  they  manage  to 
float  even  in  the  still,  draughtless  air  of  a  hot-house.  In 
this  respect  they  resemble  the  spores  of  ferns,  mosses,  and 
fungi,  which  can  hardly  come  to  the  ground  at  all  except 


Seed-Scattering  219 

when  the  air  is  almost  absolutely  motionless,  so  extremely 
light  are  they,  being,  in  fact,  rather  like  pollen  than  seeds. 
Spores,  owing  to  this  extreme  lightness,  travel  immense 
distances  over  sea  and  land,  and  are  to  be  found  in  almost 
all  dust,  whether  of  town  or  country;  but  in  damp  weather 
they  are  not  carried  so  far,  and  some  of  the  mosses  keep 
the  capsules  in  which  their  spores  are  contained  tightly 
closed  except  when  the  air  is  dry  enough  to  msure  them 
a  long  journey. 

It  might  seem  that  large,  heavy  seeds  would  be  at  a 
disadvantage  in  respect  of  wind  transport;  but  as  they 
need  a  stronger  shake  to  detach  them,  they  do  not  begin 
their  journey  till  the  wind  is  blowing  with  some  little  force; 
and  then  again,  being  generally  borne  by  trees,  and  tall 
trees,  too,  they  start  at  a  favorable  height,  and  are  often 
carried  a  long  way. 

But  we  have  been  looking  upon  seeds  hitherto  as  if 
they  were  themselves  perfectly  helpless  and  inactive,  which 
is  very  far  indeed  from  being  the  fact.  Many  of  them 
have  special  means  of  their  own  for  insuring  or  helping 
their  conveyance  from  place  to  place — means  which  vary 
according  to  the  carriers  upon  which  they  depend  for 
locomotion. 

Those  which  are  carried  by  the  wind,  for  example, 
have  elastic  spines,  wings,  feathery  tails,  down,  hairs,  all 
of  which  help  to  speed  them  on  their  way,  and  make  it 
more  easy  for  them  to  be  raised  in  the  air,  or  blown  along 
the  ground. 

Generally  as  the  lower  part  of  the  pistil  ripens,  the 
upper  part  withers,  having  done  its  work  of  conveying 
pollen  to  the  ovules.  But  sometimes  the  pistil-stalk 
remains  attached  to  the   ovary,  and  is  turned  to  a  fresh 


110  The  Great  World's  Farm 

use.  In  the  wild  clematis,  for  instance,  so  far  from 
withering  it  grows,  and  not  only  lengthens  out,  but  becomes 
silky  and  feathery,  ready  to  catch  any  puff  of  wind,  and 
very  easily  carried  through  the  air.  When  it  drops,  the 
heavier  end,  the  ovary  with  its  seed,  naturally  touches  the 
ground  first,  and  is  caught  at  last,  perhaps  after  two  or 
three  journeys,  in  damp  soil  or  moss,  or  some  crack  in  the 
earth. 

In  the  dandelion  it  is  the  upper  part  of  the  calyx  which 
enables  the  seed  to  float  through  the  air.  A  dandelion- 
blossom  is  com.posed  of  many  small  florets,  each  having 
its  own  calyx  and  pistil.  The  lower  part  of  each  pistil  is 
entirely  inclosed  in  its  own  small  calyx,  and  inseparably 
united  with  it.  The  upper  part  of  this  calyx  is  divided 
into  fine  feathery  hairs,  which  at  first  form  a  crown  to  the 
ovary,  and  look  as  if  they  grew  from  it.  But  later,  as 
the  ovary  ripens,  this  crown  is  pushed  upwards  on  a  fine 
stalk,  and  looks  like  a  miniature  parachute,  or  an  umbrella 
turned  inside  out,  and  it  catches  the  wind  as  easily,  the 
merest  breath  being  enough  to  float  it. 

We  need  not  do  more  than  mention  the  down  of  the 
thistle  and  many  other  plants,  the  wind-like  appendages 
of  the  seeds  of  the  ash,  maple,  and  sycamore,  commonly 
called  "keys,"  and  the  long,  paper-like  leaf-scales  attached 
to  the  flower-stalks  of  the  lime,  which  answer  a  similar 
purpose;  or  the  wing-like  expansions  by  which  many 
seeds  are  themselves  bordered,  and  which  act  the  part  of 
miniature  sails. 

The  seeds  of  the  water-pink  of  Ceylon  are  helped  on 
their  way  by  other  means;  they  are  inclosed  in  circular 
heads,  measuring  eight  or  nine  inches  across,  and  beset 
with    elastic    spines   which    stand    out    in    all    directions. 


WINGED  AND  FEATHERED  SEED."- 


Seed-Scattering  22 1 

These  heads  are  detached  from  the  stalks  when  ripe,  and 
are  whirled  over  the  sands  for  miles,  bounding  along  on 
the  spines,  and  dropping  their  seeds  by  the  way.  Often, 
of  course,  they  are  whirled  into  the  w^ater,  and  there  they 
float,  the  upper  spines  catching  the  wind,  and  acting  as 
sails. 

Water,  indeed,  plays  a  most  important  part  in  the  dis- 
persal of  seeds,  many  of  which,  if  carried  only  a  short 
distance  by  the  wind  to  begin  with,  may  continue  their 
journey  and  travel  much  further  if  dropped  into  river  or 
sea,  especially  if  they  happen  to  reach  one  of  the  many 
ocean-currents. 

There  are  not  many  seed-bearing  plants  which  grow 
actually  in  the  water;  but  one  of  these,  the  arrow-head, 
has  seeds  which  keep  afloat  a  long  time,  not  because  they 
are  so  remarkably  light,  but  because  they  are  so  highly 
polished  as  to  look  and  behave  as  if  they  had  been  oiled. 
They  do  not  even  become  wet,  for  water  runs  off  them; 
and  it  is  not  until  this  polish  has  been  destroyed  by  much 
rubbing  and  long  soaking  that  they  can  be  got  to  sink. 

The  seeds  of  the  water-lilies,  white  and  yellow,  are 
kept  afloat  for  some  time  by  means  of  air-bubbles.  Large 
fruits  often  float  longer  than  small  ones,  and  could  hardly 
be  transported  by  any  other  means  than  water. 

Then,  however,  comes  the  all-important  question,  how 
far  the  seeds  are  affected  by  remaining  for  some  time  in 
water;  and  here  again  they  vary  considerably,  some  being- 
far  more  hardy  than  others. 

The  coco-nut,  for  instance,  being  inclosed  in  a  mass 
of  fiber,  floats  weU,  and  is  able  to  stand  immersion  in  either 
fresh  or  salt  water  for  an  unusually  long  time,  without 
losing  the  power  of  germinating;    and  coco-palms,   self- 


222  The  Great  World's  Farm 

planted,  are  the  first  trees  to  spring  up  upon  any  newly 
exposed  coral-reef,  the  nuts  having  been  floated  thither 
from  some  more  or  less  distant  coast.  When  making 
experiments  to  ascertain  how  long  seeds  might  remain  in 
salt  water  without  being  killed,  Mr.  Darwin  was  delighted 
to  find  that  some  grew  after  twenty-one  days'  immersion. 
Many  ocean-currents,  as  he  reckoned,  travel  at  the  rate 
of  a  mile  an  hour,  so  that  these  seeds  might  be  floated  five 
hundred  miles  without  being  any  the  worse.  But,  alas! 
he  had  overlooked  one  thing.  The  seeds  had  been  under 
water  all  this  time;  and  as  Dr.  Hooker  reminded  him,  '*If 
they  sink,  they  won't  float!"  Seeds  vary  much  as  to 
the  length  of  time  they  are  able  to  remain  afloat,  and  these 
seeds  could  not  have  been  transported  at  all  by  water, 
except  under  different  circumstances,  such  as  while  they 
were  still  inclosed  in  their  seed-vessels,  or  even  attached 
to  the  plant  or  branch  on  which  they  grew. 

Some  few  seeds  grew  after  being  kept  for  one  hundred 
and  thirty-seven  days  in  sea  water;  so  that,  if  able  to 
float,  they  might  have  germinated  after  a  voyage  of  more 
than  three  thousand  miles — a  distance  greater  than  that 
which  lies  between  Europe  and  America. 

The  question  was,  then,  whether  there  were  any  way 
in  which  they  might  float ;  and  it  was  found  that  though 
ripe,  freshly  gathered  hazelnuts  sank  directly  they  were 
put  in  water,  they  would  float  for  as  much  as  ninety  days, 
and  then  germinate,  if  they  were  first  dried. 

Now  in  the  natural  state,  seeds  may  often  be  dried  by 
exposure  to  sun  and  air  before  they  are  washed,  or  blown, 
into  the  water;  and  they  would,  some  of  them  at  all 
events,  be  then  perfectly  well  able  to  float. 

Drying  does  not  answer  the  purpose  with  all  plants. 


Seed-Scattering  22^^ 

however;  but  out  of  ninety-four,  upon  which  the  experi- 
ment was  tried,  eighteen  floated  more  than  twenty-eight 
days,  and  some  much  longer,  quite  long  enough,  in  fact, 
to  allow  of  their  being  carried  from  one  continent  to 
another. 

For  Mr.  Darwin's  estimate  of  a  mile  an  hour  as  the 
rate  at  which  ocean-currents  travel  was  a  purposely  low 
one;  several  of  the  Atlantic  currents  travel  thirty-three 
miles  a  day,  and  some  as  much  as  sixty  miles  a  day,  so 
that  any  of  these  eighteen  plants  might  have  been  carried 
some  hundreds  of  miles,  and  others  from  three  to  five 
thousand,  without  their  seeds  being  any  the  worse  for  the 
voyage. 

Some  seeds  appear  to  have  no  means  at  all  of  getting 
themselves  transported  from  place  to  place;  but  it  will 
generally  be  found  that  these  are  seeds  which  have  been 
altered  by  cultivation.  The  grain  of  wheat  and  rye,  for 
instance,  falls  quite  naked  from  the  ear  as  soon  as  it  is 
ripe,  and  sinks  at  once  in  water;  and  this  is  one  reason 
why  neither  is  ever  found  wild.  Rice  is  a  little  better  off, 
for  each  grain  is  inclosed  in  a  rough,  hard  case,  which 
effectually  preserves  it  from  injury,  and  probably  in  its 
natural  state  it  was  able  to  float  on  water.  But  now  that 
its  size  and  weight  have  been  increased  by  cultivation,  it 
sinks  like  the  others. 

Seeds  may  occasionally  chance  to  be  conveyed  across 
the  ocean  in  drift-wood,  without  ever  coming  in  contact 
with  the  water  at  all;  for  stones  and  small  quantities  of 
earth  are  sometimes  found  perfectly  inclosed;  and  from 
the  earth  thus  entangled  in  the  roots  of  an  oak,  Mr.  Dar- 
win was  able  to  grow  three  plants. 

But  again,   there   is  another  way  in  which  seeds  may 


224  ^^^  Great  World's  Farm 

escape  contact  with  water:  dead  birds,  having  seeds  in 
their  crops,  may  now  and  then  escape  being  devoured,  and 
may  be  floated  long  distances  by  river  or  ocean  currents; 
and  as  many  seeds  retain  their  vitality  after  being  in  a 
bird's  crop  for  thirty  days,  some  may  be  conveyed  in  this 
way  from  time  to  time. 

The  so-called  ''goose-wheat"  of  Canada  was  first  sown 
from  grain  found  in  the  crop  of  a  wild  goose  which  was 
shot  on  its  way,  probably  from  Alaska,  or  the  Russian 
settlements  on  the  other  side  of  Behring  Strait. 


QUESTIONS  FOR  REVIEW 

1.  What  are  nature's  arguments  in  favor  of  seed-scattering? 

2.  Give   instances  of  plants  which  scatter  their  seeds  by 
explosion. 

3.  How  are  many  seeds  fitted  especially  for  transportation? 

4.  Give  the  results  of  experiments  showing  that  seeds  may 
be  carried  far  by  water. 

5.  How  are  these  seeds  sometimes  preserved  from  contact 
with  water? 


CHAPTER  XVIII 
SEED-CARRIERS 

The  seed-carriers  now  to  be  considered  are  employed 
for  the  most  part  with  as  httle  reference  to  their  own  wills, 
and  often  with  as  little  knowledge  on  their  parts,  as  the 
winds  and  waves.  The  seeds  simply  make  use  of  them 
as  carriers,  whether  they  will  or  no,  and  that  no  matter 
whether  they  be  birds,  animals,  or  even  men;  for  all  are 
pressed  into  the  service,  and  know,  for  the  most  part, 
nothing  of  what  they  are  doing.  We  are,  of  course,  not 
here  speaking  of  man's  voluntary  importations,  but  of  his 
involuntary  ones,  which  are  probably  almost  as  many. 

There  are,  however,  some  few  voluntary  carriers  among 
both  birds  and  animals — carriers  who,  though  in  one  sense 
quite  unaware  of  what  they  are  doing,  yet  for  purposes 
of  their  own  do  carry  seeds  from  one  place  to  another, 
not  very  far  probably,  but  often  the  distance  of  a  few 
miles. 

Some  birds,  for  instance,  take  a  positive  pleasure,  as 
it  would  seem,  in  carrying  things  about  for  the  mere  sake 
of  carrying  them;  and  the  propensity  is  especially  strong 
in  the  crow  tribe,  including  not  only  crows,  but  rooks, 
jays,  magpies,  and  jackdaws,  many  of  which  also  have  a 
great  love  of  hiding  as  well  as  carrying. 

On  one  occasion  a  large  number  of  fowls,  destined  for 
New  Orleans,  had  been  collected  at  some  spot  up  the  river, 
and  as  the  boat  which  was  to  convey  them  was  not  ready, 

225 


0.0.6  The  Great  World's  Farm 

they  were  turned  out  into  the  woods  for  about  a  week  to 
shift  for  themselves.  During  this  time  they  laid  about 
two  thousand  eggs  daily,  a  fact  which  seemed  immensely 
to  interest  the  crows  of  the  neighborhood.  For  whether 
with  a  view  to  eating  them,  or  simply  from  a  love  of  being 
busy,  they  devoted  themselves  to  carrying  the  eggs  away 
and  burying  them  in  a  field  more  than  half  a  mile  off  on 
the  other  side  of  a  creek.  A  month  or  two  later,  when 
the  field  was  plowed,  the  eggs  were  turned  up  in  hundreds, 
and  being  still  perfectly  good,  supplied  the  laborers  with 
many  a  meal. 

But  now,  supposing  that  the  crows  had  buried  acorns 
instead  of  eggs,  and  that  the  field  had  been  waste  ground, 
where  plovv^  and  harrow  never  came,  might  not  a  small 
forest  of  oaks  have  sprung  up?  and  may  not  many  a  plan- 
tation of  oaks,  beeches,  sycamores,  and  other  trees  have 
been  planted  in  a  similar  way? 

A  certain  pine  forest  in  Minnesota,  for  example,  on 
being  cut  down,  was  at  once  succeeded  by  oaks;  and  a 
similar  thing  is  said  to  have  occurred  in  North  Carolina, 
with  nothing  in  either  case  to  account  for  it.  The  oaks 
seemed  to  have  grown  of  themselves;  but  since  oaks  must 
certainly  spring  from  acorns,  it  seems  at  least  possible, 
and  indeed  probable,  that  crows  may  have  been  the 
planters. 

When  the  crows  assemble  in  their  hundreds  to  hold  a 
''powwow,"  or  parliament,  then  is  the  time  when  they  do 
their  sowing  on  a  large  scale;  for  true  to  their  usual 
habits,  many,  if  not  all,  bring  and  drop  something.  The 
place  chosen  for  the  assembly  is  always  open,  and  more 
or  less  bare,  and  afterwards  the  ground  may  be  seen 
strewn    with    walnuts,    hickory    nuts,  acorns,    sticks,  and 


Seed-Carriers  227 

other  rubbish.  A  certain  field  which  had  been  left  to 
itself  for  some  time  was  found  to  be  full  of  young  bur- 
oaks,  there  being  no  parent  tree  anywhere  near  from 
which  the  acorns  could  possibly  have  been  carried,  even 
by  a  high  wind. 

Now,  how  could  these  have  been  planted,  save  by 
birds?  Pigs  simply  crunch  up  and  eat  nuts  and  acorns 
where  they  find  them;  and  though  the  squirrel  sometimes 
carries  them  several  hundred  yards,  it  seldom  does  more, 
while  the  field-mouse  certainly  does  not  lay  up  her  winter 
store  very  far  from  where  her  crops  grow.  Besides, 
neither  tree-squirrels  nor  mice  act  in  concert,  and  planting 
on  so  large  a  scale  must  have  required  a  small  army  to 
accomplish  it. 

No  doubt,  however,  both  tree  and  ground  squirrels,  as 
well  as  mice,  are  responsible  for  the  planting  of  many 
a  single  nut-bearing  tree;  for  sometimes  they  may  be 
startled,  and  made  to  drop  their  treasure  before  they  reach 
home;  some  may  forget  their  storehouse,  and  some  may 
die  before  it  is  empty. 

But  the  gray  tree-squirrels  may  have  done  more,  for 
unlike  the  red  and  the  ground  squirrels  they  bury  their 
winter  store  of  nuts  and  acorns  separately,  one  by  one, 
about  a  couple  of  inches  deep;  and  though  they  have 
such  good  memories  as  to  be  able  to  find  them  again,  even 
when  buried  under  a  foot  of  snow,  no  doubt  in  many  cases 
accidents  have  happened,  and  their  stores  have  been  left 
undisturbed,  and  would  have  excellent  opportunities  of 
growing.  The  number  of  these  little  animals  in  North 
America  was  something  extraordinary  in  bygone  times; 
for  in  one  year  (1749)  six  hundred  and  forty  thousand 
were  destroved  in   Pennsylvania  alone.     They  may  well, 


22  8  The  Great  World's  Farm 

therefore,  have  done  a  great  deal  of  planting,  though  they 
would  probably  not  carry  their  nuts  far. 

The  nuthatch  often  plants  quite  a  colony  of  young 
beeches  around  its  haunts;  for  it  has  favorite  trees  to 
which  it  resorts,  after  twisting  a  cluster  of  nuts  from  the 
bough;  its  object  being  to  fix  the  nuts  in  some  crevice  of 
the  bark  where  it  may  hammer  at  them.  Very  often, 
however,  it  fails  in  the  attempt,  the  nuts  fall  to  the 
ground,  and  under  favorable  circumstances,  germinate. 

Monkeys,  also,  sometimes  carry  nuts  and  fruits  to  a 
distance  before  eating  them;  and  if  meantime  their  atten- 
tion be  caught  by  something  else,  they  will  probably  drop 
and  forget  all  about  them.  Brazil-nuts,  for  instance,  are 
inclosed  in  such  a  very  hard,  strong  outer  case  that  no 
monkey  can  get  at  the  contents,  except  by  hammering  it 
for  a  long  time  against  a  rock,  or  a  hard  log  of  wood, 
neither  of  which  is  always  to  be  found  close  at  hand. 

So  much,  then,  for  the  voluntary  carriers,  whose  work 
is  but  small  and  limited  compared  with  that  of  the  great 
army  of  involuntary  carriers. 

Look,  for  example,  at  a  dog  when  he  has  been  hunting 
in  a  ditch,  and  see  how  the  burdocks  and  goose-grass,  or 
cleavers,  have  taken  advantage  of  him,  and  made  him  act 
as  carrier  for  them. 

Now,  what  is  true  of  the  dog  in  this  respect  is  true 
also  of  many  animals,  wild  and  domestic,  including  man 
himself.  The  fleece  of  sheep,  the  fur  and  hair  of  other 
animals,  the  feathers  of  birds,  the  clothes  of  human 
beings — all  answer  the  purpose  of  these  hooked,  barbed, 
and  thorny  fruits,  by  giving  them  something  which  they 
can  lay  hold  of. 

We  have  abundant   proof  of  this  in  the  way  in  which 


Seed-Carriers  229 

more  than  one  plant  has  been  introduced  not  only  from 
one  continent  but  from  one  hemisphere  to  another  within 
recent  times. 

The  ''Bathurst  bur,"  among  others,  is  a  striking  ex- 
ample of  the  successful  emigrant.  Growing  in  Patagonia, 
it  got  itself  conveyed  to  Australia,  where  it  has  flourished 
ever  since  in  the  most  rampant  manner.  The  first  step 
was  to  hook  its  burs  into  the  tails  and  manes  of  horses, 
which  it  did  most  effectually;  and  then,  as  chance  would 
have  it,  some  of  these  same  horses  were  imported  into 
Australia,  burs  and  all,  for  so  thoroughly  were  they 
entangled  that  the  animals  had  not  been  able  to  shake 
or  rub  them  all  off,  even  during  the  voyage.  Some  no 
doubt  were  got  rid  of,  but  enough  remained  to  make  a 
fresh  start  in  the  new  country;  and  they  did  it  with  such 
energy  that  within  a  few  years  it  was  found  necessary  to 
pass  an  act  of  Parliament  ** against  the  growth  of  thistles," 
and  all  persons  allowing  them  to  remain  on  their  land,  or 
even  on  their  half  of  the  road,  were  made  liable  to  heavy 
fines. 

But  birds  are  the  great  carriers;  and  the  migrants,  espe- 
cially, transport  such  seeds  as  lay  hold  of  them  to  much 
greater  distances  than  quadrupeds ,  ever  travel,  at  least 
without  the  help  of  man. 

There  is  a  species  of  sedge  which  grows  by  the  water 
in  the  highlands  of  Jamaica,  whose  fruit  is  provided  with 
long  bristles,  something  like  a  shepherd's  crook,  the 
hooked  part  being  so  closely  fitting  and  elastic  as  to  grasp 
the  finest  hairs,  if  drawn  across  the  back  of  the  hand.  It 
grasps  them  so  tight,  moreover,  as  to  pull  them  out 
sooner  than  let  go.  The  highlands  where  this  sedge 
abounds  are  the  spots  generally  first  touched  by  migratory 


230  The  Great  World's  Farm 

birds,  and  in  some  cases  small  birds  are  caught  and  held 
so  firmly  by  the  sedge's  hooks  as  to  be  quite  unable  to 
escape.  Larger  and  stronger  birds  of  course  get  away, 
but  must  carry  many  of  the  seeds  with  them;  and  these, 
as  the  bristles  wither  and  relax  their  hold,  are  dropped  by 
the  way.  Accordingly  the  sedge  is  plentiful  all  along  the 
track  followed  by  these  birds — that  is,  the  east  coast  of 
North  America  and  the  adjacent  islands,  among  which 
the  Bermudas  especially  are  visited  by  large  numbers  of 
these  migrants. 

Birds,  such  as  the  puffins,  which  burrow  in  the  earth, 
get  their  feathers  covered  with  vegetable  mold,  which  is 
sure  to  contain  spores  and  seeds,  some  of  which  may  cling- 
long  enough  to  be  carried  at  least  part  of  the  way,  when 
the  birds  leave  their  inland  nesting-places  for  the  coast, 
where  they  spend  the  greater  part  of  the  year. 

Birds,  it  is  true,  are  generally  veiy  particular  in  keep- 
ing both  beak  and  feet  clean,  but  still  sometimes  they  are 
found  with  little  cakes  of  earth  adhering  to  them;  and 
seeds  are  so  very  common  in  all  soil,  that  some  no  doubt 
are  transported  in  this  way.  Indeed,  eighty-two  plants 
have  been  grown  from  the  earth  taken  from  the  leg  of  a 
single  partridge,  and  that  after  the  earth  had  been  kept 
three  years.  This  partridge  had  carried  as  much  as  six 
and  a  half  ounces  of  earth  on  its  leg;  and  what  one  has 
done,  others  of  course  may  do,  and  probably  have  done. 
Still,  dirt  on  feet  and  beaks  is  rare. 

The  birds  most  likely  to  have  muddy  feet  are  naturally 
the  waders,  and  those  which  frequent  the  edges  of  ponds 
and  moist  and  muddy  places.  And  these,  if  they  carry 
away  mud,  are  certain  to  carry  away  seeds  also,  for  damp 
soil  catches  and  keeps  the  seed  dropped  upon  it  in  a  way 


Seed-Carriers  221 

that  dry  soil  cannot.  From  about  a  breakfast-cupful  of 
mud  taken  under  the  water  from  the  edge  of  a  small 
pond,  Mr.  Darwin  succeeded  in  raising  five  hundred  and 
thirty-seven  plants. 

Now,  the  birds  which  frequent  bogs  and  marshes  and 
other  muddy  places  are  also  the  very  birds  which  wander 
most,  the  migrants  in  fact,  chief  among  which,  for  the 
wide  extent  of  its  journeyings,  is  the  woodcock;  for  there 
is  hardly  any  island,  however  remote,  but  the  woodcock 
finds  its  way  thither,  and  no  doubt  it  has  carried  in  its 
time  many  a  seed,  which  has  been  dropped  again  in  soil  as 
muddy  as  that  from  which  it  was  taken,  and  has  therefore 
had  a  good  chance  of  establishing  itself. 

But  though  birds  convey  seeds  both  in  their  feathers 
and  in  the  mud  on  their  feet,  they  no  doubt  convey  many 
more  in  their  crops.  There  is  no  gastric  juice  or  anything 
else  in  the  crop  to  injure  the  seeds  in  any  way,  and  when 
a  large  supply  of  food  has  been  taken,  the  grains  do  not 
all  pass  mto  the  gizzard  for  twelve,  or  even  eighteen, 
hours,  in  the  course  of  which  time  a  good  deal  might 
happen.  Birds,  for  example,  are  occasionally  blown  the 
whole  way  across  the  Atlantic,  the  wind  carrying  them  on 
at  the  rate  of  thirty-five  miles  an  hour;  and  they  might 
well,  therefore,  be  carried  five  hundred  miles  before  all 
the  grain  had  passed  out  of  their  crop,  if  they  had  just 
had  a  full  meal. 

Supposing  them  to  be  blown  over  land  instead  of  over 
sea,  or  to  reach  land  after  a  few  hours,  they  might  then 
be  pounced  on  by  the  hawks,  who  are  always  on  the  look- 
out for  weary  travelers.  These,  like  the  owls,  bolt  their 
prey  whole,  and  after  some  hours  disgorge  pellets  of 
feathers    and    other    undesirable    matter,     among    which 


232  The  Great  World's  Farm 

might  be  the  seed  in  the  crop  of  their  victim,  still  unin- 
jured. This,  indeed,  is  no  mere  speculation,  for  it  has 
been  found  by  experiment  that  such  pellets  do  contain 
seeds,  such  as  oats,  wheat,  hemp,  millet,  clover,  and 
canary-seeds;  all  of  which  may  be  capable  of  germina- 
tion. 

Seeds  vary  very  much  as  to  their  power  of  resisting 
digestion.  Many  are,  for  the  most  part,  quite  digested, 
but  there  are  others  which  are  protected  against  digestion 
by  a  covering  so  hard,  or  so  tough,  that  it  is  a  real  help 
to  them  to  be  swallowed,  as  they  germinate  more  readily 
when  this  covering  has  undergone  some  amount  of 
softening. 

Seeds,  for  instance,  which  are  swallowed,  not  for  their 
own  sake,  but  for  the  sweet  flesh  surrounding  them,  are 
more  or  less  hard,  and  some  stone-like.  Even  the  seeds 
of  elms,  firs,  and  ashes  often  escape  not  merely  unin- 
jured, but  actually  helped  by  being  swallowed;  and  the 
same  is  true,  in  a  much  more  marked  degree,  of  the 
stones  of  the  cherry,  sloe,  raspberry,  blackberry,  and 
the  seeds  of  the  apple,  and  the  tiny  nuts  of  the  straw- 
berry. 

In  some  cases  birds  render  a  positive  service  to  man 
also,  by  swallowing  and  scattering  the  seeds  of  plants 
which  he  cultivates.  All  the  present  "pimento  walks"  of 
Jamaica,  as  the  plantations  are  called,  have  been  sown  by 
birds;  for  though  the  plants  can  be  raised  in  nurseries  in 
large  numbers  by  careful  treatment,  the  planters  are  of 
opinion  that  the  seeds  are  better  prepared  by  the  birds. 
And  why  should  they  incur  the  trouble  and  expense  of 
this  "careful  treatment,"  when  the  birds  do  all  that  is 
necessary.? 


I 


Seed-Carriers 


'^33 


When  a  new  ''walk"  is  wanted,  all  that  is  necessary 
is  to  inclose  a  piece  of  waste  ground  near  an  old  "walk." 
The  birds  eagerly  eat  the  fruit  when  ripe,  and  the  seeds 
are  dropped,  with  the  result  that  twelve  months  after  the 
first  rains  abundance  of  young  plants  are  to  be  seen  grow- 
ing vigorously  in  all  parts  of  the  new  inclosure.  If  not 
inclosed,  the  plants  would  be  eaten  off  or  trodden  down 
by  wild  animals;  but  this  amount  of  protection  is  all  that 
they  require. 

Some  trees  seem  to  be  entirely  dependent  upon  birds 
for  getting  their  seeds  scattered,  and  cannot  spread  with- 
out them.  The  red  cedar  is  apparently  one  of  these;  for 
though  introduced  into  Indiana  nearly  fifty  years  ago,  it 
did  not  run  wild,  and  was  not  to  be  found  in  the  forest, 
until  some  of  the  birds  became  sufficiently  familiar  with  it 
to  venture  to  eat  the  seeds.  During  the  last  few  years 
numbers  of  young  saplings  have  made  their  appearance, 
and  it  is  likely  to  be  one  of  the  forest-trees  of  the  future. 
The  seeds  of  the  red  cedar  have  so  hard  an  outer  covering 
that  gardeners  find  it  well  to  scald  them  before  planting; 
and  it  is  therefore,  no  doubt,  a  great  advantage  to  them 
to  be  swallowed. 

How,  except  by  being  swallowed  by  birds,  does  the 
mountain-ash  berry  get  conveyed  to  the  top  of  high  walls, 
where  young  trees  may  sometimes  be  seen  growing.? 
How,  save  in  this  way,  does  the  mistletoe  reach  the  top 
of  the  oak?  or  how  do  the  wild-rose  and  privet  find  their 
way  to  the  walls  of  Cologne  Cathedral?  The  reader  may 
possibly  be  inchned  to  add  another  ''how"  to  the  series, 
and  ask  how,  when  they  get  there,  do  they  manage  to  find 
soil  to  germinate  and  grow  in?  But  as  already  remarked, 
a  very  little   soil  is  enough  for  seeds  to  sprout  in;  and 


234  The  Great  World's  Farm 

this,  in  the  case  of  buildings,  is  provided  first,  probably, 
by  the  decay  of  lichens  and  mosses  and  of  the  stone  itself, 
and  also  by  the  wind,  which  conveys  many  a  little  pile  of 
dust  into  sheltered  nooks  and  corners.  As  for  the  mistle- 
toe, being  a  parasite  and  living  by  the  labor  of  others,  it 
has  no  difficulty  about  soil,  and  makes  itself  at  home  not 
only  on  the  oak,  but  on  other  trees,  above  all  on  the 
apple. 

The  fruit-eating,  and  consequently  seed-carrying,  birds 
of  the  tropics  are  the  countless  multitudes  of  the  parrot 
tribe,  which  usually  feed  in  flocks  of  thousands,  and  wander 
far  in  search  of  food;  and  besides  these,  there  are  many 
fruit-eating  pigeons,  hornbills,  and  others.  Nor  must 
the  immense  flocks  of  large  fruit-bats,  or  flying  foxes,  be 
overlooked;  for  their  numbers  are  so  enormous  that  they 
often  take  hours  to  pass,  while  their  depredations  in  the 
orchards  are  carried  to  such  an  extent  as  to  make  them 
one  of  the  greatest  pests  of  the  tropical  fruit-grower  of 
the  East.  In  his  absence,  however,  the  fruit-eaters  have 
done,  and  do,  much  valuable  service  in  the  way  of  carry- 
ing seeds. 

Seed  cannot  be  sown  to  any  purpose  until  it  is  ripe, 
and  it  would  therefore  be  simply  wasted  if  the  birds 
carrfed  it  off  too  soon.  But  it  is  safe  enough  from  them 
while  it  is  unripe,  for  the  eatable  part,  the  flesh  surround- 
ing the  seed,  is  unripe,  too,  as  the  birds  very  weU  know, 
and  they  leave  it  severely  alone. 

Red,  yellow,  purple,  and  black  are  the  most  usual 
colors  of  ripe  fruit,  and  these  the  birds  seem,  therefore, 
to  understand  best;  for  they  seldom  touch  white  currants 
till  the  red  are  gone,  though  the  white  are  the  sweeter  of 


Seed-Carriers  235 

the  two;  and  they  have  been  observed  to  leave  unnoticed 
a  holly-tree  bearing  yellow  berries,  while  they  stripped 
other  trees  near  of  their  ordinary  red  ones.  Yellow  holly- 
berries  being  uncommon,  these  were  probably  considered 
to  be  still  unfit  for  eating. 

But  to  mention,  in  conclusion,  some  of  the  other  seed- 
carriers  besides  the  birds.  Among  these  must  be  reckoned 
fish,  locusts,  cattle,  and  perhaps  above  all,  pigs. 

Fish  swallow  the  seeds  of  many  water  and  land  plants, 
including  even  the  large  seeds  of  the  water-lily;  but  being- 
confined  to  their  own  pond,  lake,  or  river,  their  range  is 
necessarily  limited.  When,  however,  they,  in  their  turn, 
are  swallowed  by  herons,  storks,  kingfishers,  and  other 
fish-eating  birds,  the  seeds  may  be  conveyed  to  much 
greater  distances  and  be  dropped  quite  uninjured.  Some 
large  seeds  of  the  great  southern  water-lily,  for  instance, 
found  in  the  stomach  of  a  heron,  had  probably  first  been 
swallowed  by  a  fish. 

The  locusts  which  frequent  parts  of  South  Africa  are 
believed  by  the  farmers  to  have  introduced  there  various 
new  plants  which  are  injurious  to  the  grass;  and  it  is  a 
fact  that  undigested  seeds,  capable  of  germinating,  are 
found  in  their  droppings. 

Cattle  and  pigs,  but  especially  the  latter,  are  respon- 
sible for  the  rampant  way  in  which  apple-trees  are  now 
running  wild  and  forming  extensive  groves  in  the  Pampas. 
The  pips  are  so  well  protected  as  to  be  indigestible  even 
by  a  pig;  and  the  same  may  be  said  of  peach-stones, 
which  have  also  been  extensively  scattered  in  New  Zealand 
and  elsewhere,  by  similar  means  and  with  similar  results. 


226  The  Great  World's  Farm 


QUESTIONS  FOR  REVIEW 

1.  Snow  how  crows,  squirrels,  ground-mice,  etc.,  serve  as 
seed- carriers. 

2.  How  have  seeds  been  transported  in  the  hair  of  animals? 
Illustrate. 

3.  How  by  external  contact  with  birds? 

4.  Give  instances  of  the  distribution  of  seeds  used  as  food 
by  birds. 

5.  By  what  other  animal  agencies  are  seeds  scattered? 


CHAPTER    XIX 

CHANCES  OF  LIFE 

Of  all  the  wonderful  things  in  nature,  surely  a  seed  is 
one  of  the  most  wonderful.  How  dead  and  helpless  it 
looks;  how  very  little  it  tells  us  about  itself,  and  yet  how 
very  much  is  wrapped  up  in  it!  Seed:  especially  small 
seeds  from  the  same  plant,  look  just  as  much  alike  as 
grains  of  sand.  Indeed,  peas  have  become  proverbial; 
and  we  say  **as  much  alike  as  peas  in  a  pod,"  when  we 
mean  that  things,  or  people,  are  quite  without  individual 
character. 

And  yet  each  seed,  even  the  smallest  and  most  dust- 
like, has  a  character  of  its  own — a  character  which  distin- 
guishes it  not  merely  from  other  seeds  of  different  families, 
but  a  character  which  distinguishes  it  also  from  all  its 
nearest  relations,  even  from  those  which  grew  in  the  same 
pod  with  it. 

Probably  it  is  only  want  of  sight  which  prevents  our 
seeing  the  difference  between  one  seed  and  another,  for 
certainly  even  the  most  careless  observer  will  admit  that 
he  has  never  yet  found  two  perfectly  identical  plants. 
Not  even  two  peas,  taken  from  the  same  pod,  will  grow 
up  precisely  alike. 

But  as  long  as  the  seed  is  kept  from  its  natural  bed  in 
the  earth,  it  not  only  looks  dead,  but  is  dead  to  all  intents 
and  purposes,  for  it  has  no  means  of  showing  that  it 
lives — dead,    however,    with   a    possibility  of  life,   which 

237 


238  The  Great  World's  Farm 

generally  grows  less  and  less  the  longer  it  is  left  unburied. 
When  the  life  has  died  out  of  it  wholly,  it  still  looks  much 
the  same  as  before,  at  least  to  the  unpracticed  eye. 

As  to  living  seed,  if  it  be  one  that  we  know,  we  can 
tell  at  a  glance  what  sort  of  plant  bore  it,  and  what  plant 
will  spring  from  it.  But  if  it  is  a  seed  that  we  do  not 
know? 

Well,  even  then  we  may  be  able  to  tell  by  the  look  of 
it  what  family  it  belongs  to,  whether  it  is  starchy  or  oily, 
whether  it  will  have  two  seed-leaves,  like  a  bean,  or  one, 
like  corn.  But  our  knowledge  will  not  carry  us  much 
further.  In  many  cases  it  will  not  even  tell  us  whether 
the  forthcoming  plant  will  be  a  tree,  or  a  shrub,  or  a 
lowly  herb.  To  the  inexperienced,  many  of  the  smaller 
seeds  especially  look  very  much  alike;  and  there  is  cer- 
tainly no  such  difference  in  their  appearance  as  would  lead 
one  to  guess  at  the  great  variety  of  plants  which  will 
spring  from  them ;  and  even  the  wisest  knows  very  little 
about  the  why  and  the  wherefore  of  the  matter. 

For  why  should  the  small  seed  of  the  elm  produce  a 
tall  tree,  and  the  large  seed  of  the  gourd  only  a  short- 
lived, weak-stemmed,  creeping  plant?  Why  should  one 
bean  grow  to  the  height  of  a  few  inches  only,  and  another 
climb  up  several  feet?  Why,  again,  should  an  acorn 
always  produce  an  oak,  and  not  some  other  tree?  All 
that  we  can  answer  is,  an  acorn  has  oak-life  in  it.  But 
we  might  as  well  say  we  don't  know,  for  all  the  light  this 
throws  upon  the  subject. 

Look  now  at  these  seed-pods  and  seeds.  We  may 
know  that  they  have  been  taken  from  plants  of  the  great 
cabbage  family;  but  the  family  likeness  is  so  strong 
between  them  that  we  should  probably  be  puzzled  to  say 


Chances  of  Life  20 n 

which  would  produce  red  cabbages  and  which  green,  and 
from  which  will  come  crinkle-leaved  savoys,  curly-leaved 
kale,  Brussels  sprouts,  broccoli,  or  cauliflowers.  All 
these  are  but  varieties  of  the  cabbage,  though  they  are  so 
very  different  in  appearance;  and  as  long  as  they  are  only 
seeds,  they  are  so  nearly  alike  that  their  secret  is  quite  safe 
from  ordinary  people. 

Even  when  we  know  that  certain  plants  will  spring  from 
certain  seeds,  we  are  in  many  cases  quite  unable  to  tell 
what  the  color  of  the  blossom  will  be.  There  is  no  differ- 
ence at  all  to  be  detected  in  the  seed,  yet  one  seed  will 
produce  blossoms  of  one  color  and  another  of  another. 
But  why.? 

For  instance,  from  the  seed  of  the  verbena,  phlox,  and 
sweet-pea,  we  know,  because  it  has  been  so  in  the  past, 
that  we  shall  get  verbenas,  phloxes,  and  sweet-peas;  and 
we  may  go  a  step  beyond  this,  and  say  that  there  will  be 
no  quite  blue  flowers  nor  any  yellow  ones  among  them. 
This  we  know  from  experience.  We  know,  too,  that, 
though  the  seeds  of  each  sort  look  so  exactly  alike,  no  two 
plants  will  be  absolutely  similar,  and  the  blossoms  will 
vary  much.  Some  of  the  pea-blossoms  may  be  pink  of 
different  shades,  others  pink  and  white  or  purple,  though 
they  grow  side  by  side;  and  there  will  be  still  greater 
variety  in  the  colors  of  the  phloxes  and  verbenas,  some  of 
which  will  also  have  white  eyes,  and  some  not.  But  we 
cannot  tell  by  looking  at  it  which  seed  will  produce  which 
blossom. 

And  even  if,  in  some  cases,  we  should  be  able  to  do 
this,  we  are  still  not  a  whit  nearer  solving  the  mystery  of 
the  how  and  the  why.  We  may  conclude  that  there  is 
some  minute  difference  in  the  food  which  the  roots  take 


240  The  Great  World's  Farm 

up,  according  as  the  blossoms  are  of  one  color  or  another; 
for  we  know  that  the  pink  hydrangea  will  turn  blue  if  sup- 
phed  with  an  extra  amount  of  iron;  and  we  may  argue 
that,  though  the  peas  all  look  alike,  one  has  that  within 
it  which  causes  it  to  take  up  what  will  produce  pink  blos- 
soms, and  another  that  which  will  produce  purple  ones. 
But  it  is  a  mystery  still. 

We  may  prevent  their  growing  at  all,  we  may  keep 
them  till  the  possibihty  of  life  has  died  out  of  them;  or, 
though  we  let  them  grow,  we  may  prevent  their  blossom- 
ing; but  if  allowed  to  grow  and  blossom  without  interfer- 
ence, in  their  native  soil,  one  will  bear  its  pink  and  another 
its  purple  blossoms  without  fail. 

But  if  the  seed  tells  us  nothing  as  to  the  color  of  the 
blossom  which  will  spring  from  it,  it  often  tells  us  also 
just  as  little  as  to  the  size  of  the  plant  which  it  will  pro- 
duce, and  the  length  of  that  plant's  life. 

Here,  for  instance,  are  three  seeds  of  different  sizes, 
but  all  belonging  to  the  bean-like  or  leguminous  order  of 
plants.  Supposing  that  we  had  never  seen  them  before, 
and  were  told  that  one  would  produce  a  tree,  another  a 
shrub,  and  the  third  a  dwarf  annual,  should  we  be  likely 
to  guess  that,  from  the  two  smaller  seeds  would  grow  a 
laburnum  and  a  broom-plant,  while  from  the  third,  which 
is  so  many  times  larger,  would  spring  only  a  broad  or 
Windsor  bean? 

Some  of  the  orchids  bear  large  blossoms,  and  others 
large  masses  of  blossom;  yet  their  seed  is  almost  dustlike. 
The  seed  of  the  lobelia  and  of  the  scented  tobacco  is 
about  equally  minute;  but  from  the  one  springs  a  plant 
only  a  few  inches  high,  with  quite  small  blossoms; 
and    from  the    other,    one    which  grows  to   a   height    of 


Chances  of  Lif*e  241 

two  or  three  feet,  and  has  blossoms  at  least  four  inches 
long. 

Then  again,  size  of  seed  has  nothing  at  all  to  do  with 
length  of  life.  The  large  broad  bean  has  life  only  for  a 
single  season;  the  small  laburnum-seed  has  life  which 
lasts  for  years.  The  lupin,  another  leguminous  plant,  is 
both  an  annual  and  a  perennial;  but  strange  to  say,  the 
perennial  lupin  bears  the  smaller  seed,  though  it  not  only 
lives  longer,  but  is  also  the  taller  plant,  and  produces 
more  blossom  of  the  two. 

An  oak  may  live  as  many  centuries  as  a  bean  does 
months,  or  more;   but  who  can  say  why? 

The  famous  chestnut-tree  on  Mount  Etna  is  said  to  be 
ten  hundred  years  old;  and  among  other  ancient  trees, 
whose  age  is  more  or  less  well  attested,  there  is  an  oak 
reputed  to  be  sixteen  hundred  years  old  and  a  walnut  of 
nine  hundred;  there  are  olives  which  are  believed  to  be 
two  thousand  years  old;  and  there  is  at  least  one  tree  in 
the  East  which  tradition  affirms  to  be  even  six  thousand 
years  old!  But  again,  why  an  olive  should  outlive  an 
oak,  who  can  say.'* 

There  is  a  great  difference,  also,  as  to  the  length  of 
time  during  which  the  seeds  themselves  retain  their  vital- 
ity or  power  of  germinating.  Most  of  them  look  equally 
lifeless;  but  in  some  this  mysterious  power  lasts  much 
longer  than  in  others,  and  this,  too,  with  very  little  refer- 
ence to  their  size,  though  large  seeds,  especially  oily 
seeds,  have  some  advantage.  The  seed  of  the  coffee- 
berry,  for  instance,  is  worthless  unless  planted  without 
delay  directly  it  is  ripe;  and  willow-seed  is  said  to  live 
only  a  fortnight  after  ripening,  or  less  if  it  is  allowed  to 
become  dry.     Seeds  of  melon  and  geranium,  on  the  other 


242  The  Great  World's  Farm 

hand,  have  been  known  to  germinate  after  being  kept, 
merely  wrapped  in  paper,  for  thirty  years.  It  is  believed 
that  if  melon-seeds  produce  plants  at  all  after  being  kept 
for  some  time,  their  crop  of  fruit  will  be  all  the  larger; 
but  they  are  commonly  supposed  not  to  live  longer  than 
seven  years,  and  even  within  this  period  the  longer  they 
are  kept  the  smaller  is  their  chance  of  germinating  con- 
sidered to  be. 

Cases,  however,  have  been  known  in  which  certain 
seeds,  quite  small  seeds,  too,  have  kept  the  life  in  them 
not  only  for  years,  but  for  centuries,  and  even  millenni- 
ums. We  are  not  alluding  to  the  famous  mummy- wheat  ; 
for  the  grain  of  wheat,  being  quite  unprotected  except  by 
a  thin  husk,  loses  all  power  of  germinating  in  a  few  years 
at  most;  and  none  of  the  interesting  stories  told  of  wheat 
raised  from  grain  found  in  Egyptian  tombs  have  ever  yet 
been  satisfactorily  proved. 

Grain  taken  from  mummies  has  germinated  sure 
enough,  but  it  has  been  grain  recently  introduced  by  the 
Arabs!  In  one  instance  the  plant  raised  bore  oats;  but 
this  was  unlucky,  for  oats  were  not  known  to  ancient 
Egypt;  and  in  no  single  case  has  any  success  attended 
the  innumerable  attempts  made  to  raise  plants  from  genu- 
ine mummy-wheat.  But  seeds  found  in  Roman  tombs 
have  not  only  germinated,  but  produced  plants. 

Of  all  well-authenticated  cases,  however,  the  most 
remarkable  is  that  of  the  seedlings  raised  by  Dr.  Lindley, 
in  Chiswick  Gardens,  from  raspberry  seeds  found  in  Celtic 
tumuli  perhaps  some  two  thousand  years  old.  Raspberry 
seeds  have  very  hard  coats,  it  is  true,  and  these  seeds 
were  safely  buried  from  the  air,  and  beyond  the  reach  of 
any  great  changes  of  temperature;   but  yet  that  things  so 


Chances  of  Life  243 

small  should  have  been  able  to  preserve  Hving  germs 
within  them  for  so  long  a  time  is  a  wonderful  proof  of 
their  great  tenacity  of  life. 

Generally  speaking,  it  seems  that  the  seeds  of  wild 
plants  have  the  advantage  over  the  cultivated  in  this 
respect.  They  retain  their  vitality  longer;  but  then,  on 
the  other  hand,  there  are  not  so  many  of  them.  Culti- 
vated plants  usually  produce  most  seed— except,  of  course, 
where  blossoms  have  been  doubled  or  fruit  improved  at 
its  expense. 

When  one  considers  the  vast  quantity  of  seed  produced, 
and  the  ample  contrivances  for  scattering  it,  it  is  surpris- 
ing to  find  that,  after  all,  many  plants  do  not  increase 
their  numbers  at  alL  There  are  just  about  the  same 
number  of  them  now  that  there  were  years  ago — neither 
more  nor  fewer. 

Take,  for  example,  the  common  wild  spotted  orchis, 
a  single  plant  of  which  often  bears  as  many  as  thirty  seed- 
vessels,  each  containing  six  thousand  two  hundred  seeds. 
Suppose  that  there  were  four  hundred  bad  seeds  to  each 
capsule,  twelve  thousand  in  all,  which  is  a  fair  allowance, 
one  plant  might  still  be  the  parent  of  one  hundred  and 
seventy-four  thousand  others — enough  to  cover  nearly  an 
acre  of  ground  if  the  plants  grew  just  far  enough  apart  to 
allow  a  proper  amount  of  space  to  each.  The  descend- 
ants of  these,  again,  might  more  than  cover  the  Isle  of 
Anglesey,  and  the  great-grandchildren  of  the  one  original 
plant  would  more  than  clothe  the  entire  land  surface  of 
the  globe! 

This  calculation  was  made  by  Mr.  Darwin;  and  yet, 
as  he  goes  on  to  observe,  the  plant  is  actually  not  increas- 


244  The  Great  World's  Farm 

ing  at  all  in  most  places,  although  it  is  a  perennial,  and 
although  its  seeds  are  so  minute  as  to  be  easily  wafted  to 
a  great  distance  by  the  wind.  So,  .then,  only  one  seed 
out  of  the  thousands  borne  by  a  single  plant  can  come  to 
anything,  and  even  that  not  every  year,  but  only  once  in 
several  years;  for  as  each  plant  lives  some  years,  there 
must  be  an  increase  in  its  numbers  if  but  one  new  plant 
grew  up  every  year. 

That  the  seeds  are  scattered,  and  widely  scattered,  is 
unquestionable,  for  seedlings  have  been  found  eight  or  ten 
miles  away  from  where  any  plants  grew;  but  it  is  equally 
certain  that  there  is  some  effectual  check  to  the  plant's 
increase,  though  what  that  check  is  remains  unknown. 

It  is  plain,  therefore,  that  the  mere  scattering  of  the 
seed,  however  necessary  as  a  first  step,  is  far  from  being 
enough  to  secure  that  the  plant  shall  be  able  to  establish 
itself  in  a  fresh  locahty;  and  the  farther  the  seed  is 
carried  the  greater  the  risk  it  often  runs.  Some  plants 
are  much  better  able  than  others  to  adapt  themselves  to 
altered  circumstances,  and  these,  of  course,  make  the 
better  colonists;  but  even  they  may  be  quite  unable  to 
effect  a  settlement,  simply  for  lack  of  space.  Others  find 
that  soil,  or  climate,  or  situation  do  not  suit  them,  and 
soon  die  out  for  that  reason.  Others,  again,  though  they 
may  find  ample  room,  and  all  things  else  to  their  liking, 
are  quite  unable  to  become  permanent  colonists  because 
they  cannot  fertilize  themselves,  and  if  there  are  not  the 
right  insects  to  do  it  for  them,  they  cannot  produce  any 
seed.  Such  plants  as  have  more  than  one  "form,"  and 
such  as  bear  pollen  and  ovules  on  separate  individuals,  run, 
of  course,  especial  risks  when  they  migrate,  as  one  is 
generally  helpless  without  the  other. 


Chances  of  Life  245 

In  the  matter  of  soil,  too,  a  very  short  distance  often 
makes  a  great  difference.  The  bee-orchis,  for  example, 
grows  plentifully  on  the  chalk  in  Surrey,  and  one  year  it 
suddenly  made  its  appearance  in  a  clayey  field  near 
Thames  Ditton,  where  it  had  never  been  seen  before. 
About  a  hundred  plants  blossomed  in  this  one  field,  and 
nowhere  else  in  the  neighborhood.  But  they  gradually 
dwindled  away,  and  in  the  course  of  six  or  eight  years  all 
had  entirely  disappeared.  The  seeds  had  probably  trav- 
eled to  the  clay-field  in  some  chalk  which  had  been  brought 
from  another  part  of  the  county,  but  the  colony  could  not 
be  a  lasting  one  for  some  reason — most  likely  owing  to 
the  change  of  soil,  and  perhaps  also  of  situation. 

European  plants,  to  the  number  of  more  than  a  hun- 
dred and  fifty,  have  been  quite  successful  in  New  Zealand, 
and  are  thoroughly  established;  but  it  is  remarkable  that 
while  so  many  European  plants  have  made  themselves  at 
home  there,  only  two  or  three  Australians  have  managed 
to  do  so.  Yet  Australia  is  nearer  than  Europe,  and  the 
intercourse  between  the  two  countries  is  much  more  close 
and  frequent  than  it  is  with  Europe.  Moreover,  Austra- 
lian seeds  have  been  purposely  and  extensively  scattered 
in  New  Zealand,  among  them  being,  we  may  be  sure,  the 
seeds  of  such  common  kinds  as  those  of  the  acacia  and 
eucalyptus,  yet  none  of  these  trees  are  to  be  seen  grow- 
ing wild. 

It  is  the  same  with  our  own  garden-plants.  How  many 
there  are  which,  though  they  grow  in  the  garden  without 
any  special  care,  and  bring  abundance  of  seed  to  perfec- 
tion, yet  never  run  wild,  even  to  the  extent  of  appearing 
on  just  the  other  side  of  the  wall  or  hedge!  Yet  it  is 
impossible  to  suppose  but  that  the  seed  is  often  carried 


246  The  Great  World's  Farm 

beyond  these  limits;  and  weeds  make  their  way  in  with- 
out difficulty. 

In  considering  what  becomes  of  the  vast  amount  of 
seed  which  is  annually  ripened,  we  must,  of  course,  bear 
in  mind  that  a  great  deal  is  consumed  as  food — luckily  for 
us;  for  if  there  were  no  seed-eating  birds,  we  should  be 
overrun  with  thistles  and  other  weeds.  Some  seed  also 
falls  upon  soil  which  does  not  suit  it;  some  requires  bury- 
ing, and  gets  killed  by  remaining  exposed;  some  cannot 
germinate  without  special  preparation  of  itself  or  the  soil, 
or  both;  still  more,  if  transported  to  a  distance,  will  find 
the  climate  unsuitable. 

But  in  many  cases  want  of  space  is  the  only  obstacle, 
and  a  very  serious  one  it  is.  There  is  generally  plenty  of 
room  for  weeds  in  a  garden,  and  they  are  not  slow  to  take 
advantage  of  it;  for  there  is  a  good  deal  of  crowding  on 
the  other  side  of  the  wall,  where,  in  fact,  a  constant  strug- 
gle for  existence  is  going  on,  and  only  the  stronger  sur- 
vive. Seeds  falling  upon  ground  already  covered,  and 
thickly  covered,  with  vegetation,  as  a  hedge-bank  gener- 
ally is,  have  but  little  chance.  In  fact,  they  hardly  reach 
the  soil  at  all,  the  great  majority  of  them. 

Look  among  the  long  meadow-grass,  and  you  may 
often  see  hundreds  and  thousands  of  downy  seeds  caught 
among  the  stems  and  suspended,  each  with  its  seed  point- 
ing downwards,  ready  to  take  advantage  of  any  crack  in 
the  soil  in  which  to  insert  itself,  but  quite  unable  and 
unlikely  to  reach  it.  And  even  of  the  seeds  which  do 
reach  it,  how  many  must  find  that  the  first-comers  are 
stronger  and  better  fitted  for  the  situation  than  them- 
selves! and  so,  even  if  they  spring  up,  they  are  speedily 
overpowered  and  crowded  out. 


Chances  of  Life  247 

The  number  of  seeds  produced  varies  enormously  in 
different  plants.  Orchids  produce  them  at  the  rate  of 
thousands  to  each  blossom;  and  some  of  the  foreign 
species  go  far  beyond  this,  a  single  seed-vessel  containing 
more  than  a  million  and  three-quarters  of  seeds.  The 
blossom  of  an  oak,  on  the  other  hand,  produces  but  one 
seed.  But  the  advantage  is  not  all  on  the  side  of  num- 
bers; for  the  greater  the  number  the  smaller  the  size; 
and  the  smaller  the  seed  the  smaller  the  germ,  and  also 
the  smaller  the  supply  of  ready-made  food  with  which  it 
begins  life.  A  large  seed,  such  as  a  bean,  has  a  large, 
strong  germ;  and  its  two  thick  seed-leaves,  which  are 
really  store-cupboards,  can  supply  the  seedling  with  plenty 
of  food,  so  that  it  starts  with  much  in  its  favor.  And  so 
ten  large  seeds  will  often,  it  is  said,  yield  more  plants 
than  some  thousands  of  small  ones. 

Neither  the  acorn  nor  the  chestnut,  when  it  has  left  its 
shell,  has  anything  to  protect  it  except  its  color,  which, 
being  like  that  of  the  earth,  or  of  dead  leaves,  may  some- 
times enable  it  to  escape  notice  as  it  lies  on  the  ground; 
and  if  but  one  escapes  now  and  then,  at  long  intervals, 
once  in  a  few  centuries,  the  stock  will  be  kept  up,  though 
not  increased. 

Small  seeds  have  a  better  chance  in  some  ways,  as 
they  are  more  easily  sheltered,  and  hidden  from  the  bright, 
keen  eyes  of  the  birds.  A  bed  of  damp  moss  is  a  capital 
hiding-place;  and  so  are  the  cracks  which  open  in  the  soil 
when  the  earth  is  dry;  for  these  close  up  again  when  the 
wet  comes,  and  the  seeds  are  safely  buried  out  of  harm's 
way.     Cracks  may  often  be  seen  full  of  seeds. 

Still,  "if  you  want  a  thing  done,  do  it  yourself,"  is  an 
excellent  motto  even  for  seeds,  and  it  is  an  advantage  to 


248  The  Great  World's  Farm 

be  independent  even  of  cracks;  this  is  what  some  seeds 
are,  especially  a  good  many  grass-seeds;  for  instead  of 
waiting  to  be  buried,  they  set  to  work  and  bury  themselves. 
The  seed  of  the  grass  Aristida,  for  instance,  is  inclosed 
in  a  couple  of  husks  tipped  with  bristles,  each  divided 
into  three  fine  tails,  six  or  eight  inches  long,  which  stand 
out  in  different  directions  more  or  less  at  right  angles  to 
the  seed.  When  the  seed  falls  to  the  ground  the  tails 
keep  it  upright,  and  as  they  dry  and  twist,  they  make  it 
turn  round  and  round  on  its  point,  which  is  barbed  with 
flint;  and  so  it  bores  its  way  into  the  earth,  the  barb  hold- 
ing it  fast,  so  that  it  cannot  be  blown  away  by  wind. 

Another  self-burying  seed  is  that  of  one  of  the  crane's- 
bills,  which  is  nearly  related  to  the  geranium.  The  fruit 
of  this  little  plant  consists  of  four  or  five  miniature  arrows, 
which  are  the  hardened  and  much  lengthened  carpels,  each 
having  its  ovary  (containing  a  single  seed)  at  the  lower 
end.  At  first  they  are  fitted  closely  together  round  a 
central  spike,  and  form  the  "beak,"  with  which  we  are  all 
familiar  in  the  geranium.  But  when  they  are  ripe,  they 
separate  at  the  lower  end,  and  begin  to  twist  like  a  cork- 
screw, still  holding  together  at  the  tip,  however,  for  a 
time.  Each  arrow  is  fringed  on  the  inner  side  with  short 
stiff  hairs,  and  the  ovary  is  pointed  and  barbed  in  a  special 
manner.  They  are  readily  carried  by  the  wind  therefore, 
besides  also  clinging  easily  to  the  coats  of  animals;  and 
when  at  last  they  drop  singly  to  the  ground,  the  barbs 
catch  in  the  soil  and  hold  them  fast.  The  shafts  of  the 
arrows  twist  more  and  more  the  drier  they  grow,  and  as 
they  twist,  they  turn  the  seed  deeper  and  deeper  into  the 
ground. 

Some  seeds  have  many  more  difficulties  in  the  way  of 


Chances  of  Life  249 

their  growing  than  others.  For  with  some,  it  is  abso- 
lutely necessary  that  they  should  be  buried  before  they 
can  even  begin  to  germinate;  while  others,  though  they 
may  be  able  to  germinate  without  help  or  preparation  of 
any  kind,  find  it  by  no  means  easy  to  do  more  than  make 
the  first  start. 

With  some,  germination  is  an  easy  matter  enough,  all 
that  they  need  being  a  little  moisture.  Such  is  the  mus- 
tard-seed, which  will  sprout,  and  even  grow  for  a  time, 
on  any  damp  surface;  a  piece  of  flannel,  or  even  the  out- 
side of  a  porous  earthenware  jar  will  do,  if  only  this  is 
kept  filled  with  water.  Other  seeds  begin  to  shoot  even 
before  they  leave  the  parent-plant.  The  seeds  of  a  species 
of  convolvulus  put  forth  quite  large  leaves  before  they 
burst  the  pod;  and  in  hot  climates,  the  seed  of  the  water- 
melon sometimes  grows  in  like  manner,  within  the  fruit. 

Brazil-nuts  also  begin  sprouting  before  the  hard  outer 
case  in  which  they  are  inclosed  shows  any  sign  of  decay; 
but  though  they  may  all  sprout,  only  one  of  the  whole 
number  seems  to  have  a  chance  of  doing  more  under 
ordinary  circumstances.  There  are  from  twelve  to  fifteen 
nuts — or,  strictly  speaking,  seeds — in  each  ovary  or  case, 
which  is  filled  with  the  matted  roots  sent  out  by  one  and 
all.  At  the  lower  end,  where  the  fruit  was  attached  to 
the  stalk,  there  is  a  small  opening,  and  the  fortunate  indi- 
vidual which  gains  possession  of  this  exit  may  eventually 
burst  the  case  with  its  roots,  and  so  make  its  way  into  the 
soil.  But  the  shell  of  the  case  is  extremely  hard,  and  so 
far  as  has  been  observed,  it  is  not  often  that  even  one 
single  plant  succeeds  in  freeing  itself.  But  then,  on  the 
other  hand,  if  the  shell  were  less  hard,  none  would  prob- 
ably ever   escape  the  hosts   of  animals  ready   to  devour 


250  The  Great  World's  Farm 

them;  for  sprouted  nuts,  taken  out  of  the  case  and 
planted,  have  been  found  to  be  all  dug  up  and  eaten  by 
rats. 

With  the  exception  of  the  sugar-maple,  none  of  the 
forest-trees  or  the  evergreens  seem  to  have  children  grow- 
ing up  round  them  in  Indiana.  Seeds  of  white  pines,  firs, 
American  poplars,  etc.,  when  they  fall  upon  the  scattered 
leaves  of  the  parent-tree,  simply  lie  there  and  die;  and 
their  almost  only  chance  of  life  seems  to  be  when  they  fall 
upon  some  little  bed  of  earth  made  by  the  hogs,  which 
root  about  among  the  leaves  and  turn  up  mold  while  they 
are  searching  for  worms. 

One  would  not  suspect  hogs  of  doing  any  useful  work 
of  this  sort;  but  these  animals,  which  have  been  turned 
loose  in  the  woods,  do  seem  to  have  planted  many  clusters 
of  young  poplars,  for  the  edge  of  the  trees  just  corresponds 
with  the  date  when  the  pigs  were  first  brought  into  the 
settlement. 

A  change  deserving  of  notice  has  been  wrought  in 
some  parts  of  the  Riverina,  New  South  Wales,  solely,  as 
it  would  seem,  by  the  introduction  of  cattle.  In  the  old 
times  there  were  not  animals  enough  to  eat  the  grass 
down;  and  so  when  it  became  ripe  and  dry,  it  was  easily 
set  alight  by  a  chance  spark  from  the  fire  of  a  native. 
The  natives  were,  indeed,  suspected  of  firing  it  on  pur- 
pose to  insure  a  fresh  crop  to  tempt  the  kangaroos  within 
their  reach.  Any  seeds  of  eucalyptus  or  other  trees  were 
either  killed  in  the  conflagration  or  by  exposure  to  the 
weather,  for  they  lay  on  the  surface  of  the  ground,  with 
no  animal  sufficiently  heavy  of  foot  to  tread  them  in;  and 
it  would  seem  that  their  only  hope  could  be  in  chance 
cracks.     Trees  were   accordingly   scarce   in  these  parts; 


Chances  of  Life 


^5 


but  the  scarcity  evidently  arose,  not  from  want  of  seed, 
but  from  want  of  opportunity  for  its  growth.  For  all  now 
is  altered:  the  cattle  tread  the  seeds  in,  and  don't,  appar- 
ently, eat  the  young  plants  which  spring  from  them;  for 
dense  forests  and  scrubs  have  arisen — not  to  the  satisfac- 
tion of  the  graziers,  who  would  prefer  grass  alone. 

Some  seeds  appear  to  have  only  an  occasional  chance 
of  germinating  in  a  state  of  nature;  for  they  must  either 
be  scalded,  or  scorched,  or  very  hard  frozen  before  they 
can  sprout  at  all,  and  even  then  they  cannot  prosper  unless 
they  have  a  clear  field,  with  no  other  plants  to  interfere 
with  them.  This  is  the  case  with  the  seeds  of  the  black 
locust-tree,  which  are  easily  carried  by  the  wind,  and  are 
so  very  hard  that  they  may  lie  exposed  for  years  without 
being  any  the  worse  for  it,  it  is  true,  but  also  without 
being  able  to  germinate.  If  they  were  less  long-lived, 
they  would  probably  die  before  their  opportunity  came. 
But  if,  when  a  clearing  is  made  in  the  forest,  the  trees 
should  be  fired  and  the  ground  burned  bare,  as  it  is  some- 
times, then  comes  their  long-waited-for  opportunity,  and 
up  they  spring  in  numbers  wherever  the  fire  has  passed. 

The  seeds  of  a  certain  species  of  cedar  could  not  be  got 
to  grow  at  all  at  the  Cape  until  they  had  been  thoroughly 
boiled.  Such  very  hard-coated  seeds  are  well  protected 
against  injury,  but  in  a  state  of  nature  they  must  be 
dependent  upon  fires,  frost,  or  perhaps  on  being  swal- 
lowed, for  the  opportunity  of  growing. 

Other  seeds,  again,  though  they  require  no  special 
preparation  of  themselves  or  the  soil,  are  quite  unable  to 
germinate  unless  they  get  rain  immediately  after  they  have 
fallen,  and  that,  too,  continued  for  some  little  time. 

Thus  the  ''soft  maples"  planted  in  the  streets  of  Rock- 


2§2  The  Great  World's  Farm 

ville,  Indiana,  though  they  have  borne  seed,  have  never 
succeeded  in  sowing  themselves  till  within  the  last  few 
years,  as  a  single  day's  exposure  to  the  hot  sun  is  fatal 
both  to  seeds  and  seedlings,  and  even  daily  watering  often 
proves  insufficient  to  keep  the  latter  alive.  In  the  wild 
state  they  spring  up  only  in  very  moist  or  watery  places, 
though  later  on  they  will  bear  transplanting  to  dry  soil. 

One  year,  however,  there  was  a  storm  which  shook 
down  such  a  quantity  of  seed  that  the  streets  of  Rockville 
were  yellow  with  it.  Then  followed  several  days'  rain, 
with  sunny  intervals,  and  the  seeds  sprouted  everywhere, 
all  over  the  streets,  in  the  yards  and  the  gardens,  as  thick 
as  weeds — a  sight  never  seen  before. 

How  is  it  that  European  weeds  have  spread  so  exten- 
sively in  the  United  States,  while  Australian  seeds,  widely 
and  purposely  scattered  in  New  Zealand,  have  gained  no 
footing.^ 

First  and  chiefly  because  in  the  one  case  there  was  a 
vacancy,  and  in  the  other  there  was  none.  The  vacancy 
in  America  was  not  natural,  but  caused  by  the  cutting 
down  of  forests  and  the  dying  off  of  the  undergrowth, 
which  vvras  killed  by  sudden  exposure.  Of  course,  there 
were  plenty  of  plants  in  America  which  would  have 
stepped  in  and  taken  possession  in  time,  but  they  were 
too  far  off,  on  the  plains  and  prairies  of  the  great  Missis- 
sippi Valley,  to  do  it  quickly  enough,  and  meantime  the 
foreigners  arrived.  Weeds  from  Europe  were  introduced 
with  grass  seed  and  corn  seed,  and  in  other  ways,  and 
when  the  forest  lands  were  turned  into  pastures  and 
fields,  these  weeds  had  as  good  a  chance  of  thriving  as 
they  had  at  home. 

It  would  be  a  different   matter  if  they  were  to  arrive 


Chances  of  Life  253 

now,  for  meantime  other  changes  have  taken  place  which 
have  made  it  easier  for  plants  to  come  from  the  West,  and 
they  do  come.  New  Western  plants  migrate,  it  is  said, 
almost  every  year  into  the  Eastern  states. 

And  how  do  these  new  plants  travel.?  By  rail,  to  be 
sure,  in  accordance  with  the  spirit  of  the  age.  They 
come  in  the  coats  or  in  the  food  of  cattle  going  to  market, 
and  they  take  advantage  of  the  bared  railway  borders, 
which  are  such  excellent  nursery-grounds.  The  great 
railroads  run  east  and  west,  and  as  the  prevailing  winds 
are  westerly  and  very  strong,  the  plants  of  the  West  are 
now  amply  provided  with  the  means  of  transport.  The 
seeds  also  find  vacant  spots  on  which  to  alight,  and  by 
which  they  may  break  the  journey,  and  finally  they  are 
transported  into  a  climate  not  greatly  unlike  their  own,  so 
that  they  have  much  in  their  favor. 

Plants  travehng  east  and  west  have  a  much  better 
chance  of  finding  a  climate  to  suit  them  than  those  which 
travel  north  and  south,  except,  of  course,  such  as  cannot 
thrive  without  sea  air,  like  the  holly,  which  cannot  live  at 
all  more  than  a  hundred  miles  from  the  coast.  But  of 
the  plants  which  travel  north  and  south,  those  generally 
have  the  better  chance  which  travel  from  a  cold  climate 
to  a  warmer  one.  Increased  warmth  is  better  borne  than 
increased  cold,  and  the  plants  of  temperate  latitudes  have 
stronger  and  more  vigorous  constitutions,  such  as  give 
them  great  advantages. 

See,  for  instance,  how  they  have  thriven  in  the  Pampas 
district  of  South  America,  in  some  parts  of  which  there 
is  hardly  a  native  plant  to  be  seen  for  miles,  so  completely 
have  the  new-comers  ousted  them.  For  the  giant 
** thistles"  and  the  luxuriant  clover,  already  described,  are 


2  54  The  Great  World's  Farm 

not  natives,  but  colonists.  The  fatherland  of  the  arti- 
choke family,  to  which  the  "thistle"  belongs,  is  on  the 
shores  of  the  Mediterranean,  and  from  thence  "thistles" 
and  clover  were  probably  introduced  by  the  Spaniards. 
And  they  not  only  found  the  soil  and  climate  suitable, 
but  a  still  greater  point  in  their  favor,  they  found  the 
ground  very  scantily  occupied  by  native  vegetation. 

There  had  not  been  time  to  plant  this  corner  of  the 
world's  farm  thoroughly,  for  it  had  been  under  water 
until  comparatively  recent  times — recent,  geologically 
speaking,  that  is.  And  when  it  became  dry  land  there 
were  few  plants  and  no  trees  at  hand  to  colonize  it. 

There  was  abundant  vegetation  to  the  north,  however, 
and  that  of  the  most  luxuriant  kind,  and  most  of  the  early 
colonists  came  from  there.  But  they  were  too  delicate  to 
bear  well  the  change  to  such  much  cooler  regions,  and 
only  a  few  managed  to  settle  down  and  really  flourish;  so 
that  when  the  Europeans  came,  strong  and  vigorous,  they 
soon  overpowered  these  previous  colonists,  which  had  but 
scantily  occupied  the  ground,  and  themselves  grew  in  a 
rampant  manner.  Any  delicate  new-comers  arriving  after 
such  sturdy  emigrants  as  these  would  naturally  have  no 
chance  at  all. 

Plants  may  find  a  vacant  or  almost  vacant  spot,  and 
they  may  like  the  soil,  and  even  the  climate,  but  if  they 
are  dependent  upon  any  particular  insect  for  fertilization 
they  will  not  be  able  to  perfect  their  seed  without  it;  and 
if  they  cannot  do  this  they  can  never  become  naturalized, 
and  must  needs  in  most  cases  die  out. 

Of  plants  which  require  help,  those  are  most  likely  to 
prosper  whose  blossoms  are  least  peculiar  in  shape,  and 
most    accessible.     Tubular  blossoms,    such  even  as    the 


Chances  of  Life  255 

common  clovers,  require  insects  with  trunks  of  some 
length,  because  their  nectar  is  so  deeply  hidden  that  none 
but  these  can  reach  it.  And  insects  do  not  visit  flowers 
where  there  is  nothing  to  be  gained. 

Composite  flowers,  such  as  the  daisy,  dandelion,  camo- 
mile, groundsel,  and  many  others  whose  blossoms  grow 
together  in  flat  heads,  are  easily  fertilized  by  almost  any 
insects;  and  what  with  this  advantage,  and  the  further 
one  that  so  many  of  the  family  have  downy  seeds  easily 
carried  by  the  wind,  composites  are  among  the  most  thriv- 
ing and  successful  emigrants. 


QUESTIONS  FOR  REVIEW 

1.  What  questions,  difficult  to  answer,  are  suggested  by  the 
seeds  of  various  plants? 

2.  What  interesting  cases  have  been  known  of  seeds  which 
kept  their  life  for  hundreds  of  years? 

3.  What  truth  is  suggested  by  the  fact  that  the  wild  orchis 
does  not  increase? 

4.  What  difficulties  may  plants  encounter  in  new  localities? 

5.  What  may  happen  to  seeds  before  they  even  begin  to 
grow? 

6.  How  do  some  seeds  bury  themselves? 

7.  What  difficulties  does  the  Brazil-nut  encounter? 

8.  What  change  was  brought  about  by  cattle  in  New  South 
Wales? 

9.  Give  examples  of  seeds  helped  by  being  scorched,  boiled, 
and  soaked. 

10.  Why  have   European  seeds   flourished  in   the   United 
States? 

11.  How  do  Western  plants  migrate? 

12.  What  fact  is  illustrated  by  the  Pampas  district  of  South 
America? 

13.  Why  are  composites  apt  to  be  successful  emigrants? 


CHAPTER   XX 

FRIENDS  AND  FOES 

From  one  point  of  view  all  animals,  with  the  exception 
of  a  few  insects,  may  be  looked  upon  as  enemies  of  the 
plant-world,  since  they  either  themselves  feed  upon  plants, 
or  live  on  others  who  do.  But  this  would  be  a  very 
partial  view  of  the  matter,  even  where  the  destruction  is 
complete;  for  it  is  a  positive  benefit  to  the  race  that  the 
greater  number  of  seedlings,  as  well  as  seeds,  should  be 
devoured,  or  otherwise  removed,  since  without  this  thin- 
ning of  their  numbers  none  could  come  to  perfection. 

Linnaeus  calculated  that  any  one  annual  which  pro- 
duced but  two  perfect  seeds — its  descendants  doing  the 
same  every  year — would  have  increased  to  a  million  in  the 
course  of  twenty  years.  Now  all  annuals  do  considerably 
more  than  this  as  a  rule;  and  as  they  do  not  increase  at 
an  alarming  rate,  it  is  evident  that  their  existence  must  in 
many  instances  be  cut  short,  at  one  time  or  other  of  their 
career. 

Plants  have  many  and  various  enemies  which  attack 
them  at  different  stages  of  their  lives,  but  it  is  chiefly 
while  they  are  seedlings  that  they  are  altogether  extermi- 
nated, as  they  often  are  wholesale.  Out  of  three  hundred 
and  fifty-seven  seedling  weeds  growing  together  without 
any  crowding  in  a  small  plot  of  ground,  Mr.  Darwin 
found  that  two  hundred  and  ninety-five  were  destroyed, 
mainly  by  slugs  and  insects. 

256 


Friends  and  Foes  257 

From  the  point  of  view  of  the  destroyed — the  victims — 
these  creatures  were  undoubtedly  foes;  but  from  that  of 
the  survivors  they  were  as  certainly  friends,  for  the  latter 
would  grow  up  all  the  more  vigorous  for  having  plenty  of 
space. 

But  if  slugs  and  insects  were  allowed  to  multiply  with- 
out check,  they  would  become  foes  and  nothing  else,  and 
would  end  by  eating  up  every  green  thing.  There  are 
checks  upon  their  increase,  however;  and  besides  this, 
many  plants  are  to  some  extent  protected  against  them, 
as  otherwise  certain  species  might  be  exterminated 
altogether. 

Plants  like  the  grasses,  which  bear  vast  quantities  of 
seed,  are  protected  by  their  very  numbers,  and  can  well 
afford  to  be  eaten,  if  but  a  small  proportion  be  allowed  to 
perfect  and  disperse  their  seed;  but  others,  less  prolific, 
are  guarded  in  various  ways,  being  made  either  disagree- 
able or  difficult  of  approach. 

The  whole  of  the  Gentian  order,  for  example,  are  so 
extremely  bitter,  that  they  are  seldom  touched  even  by 
caterpillars;  and  the  Eschscholtzia,  which  is  of  another 
order,  is  also  so  intensely  bitter  as  to  be  more  avoided  by 
slugs  and  the  like  than  any  other  plant,  it  is  said.  Even 
Eschscholtzias  are,  however,  a  good  deal  bitten  at  times, 
probably  by  earwigs,  but  this  may  be  owing  to  drought 
and  consequent  scarcity  of  vegetable  matter,  as  it  is  not  a 
common  occurrence.  It  is  at  least  something  to  be  proof 
against  certain  classes  of  enemies;  and  no  plants  are 
defended  against  all,  since  they  are  intended  to  be  eaten, 
though  not  exterminated. 

The  bark  of  oaks,  elms,  and  willows  is  made  sufficiently 
unpleasant  to  most  animals  by  the  presence  of  tannin;  and 


258  The  Great  World's  Farm 

ferns  contain  so  much  of  this  that  few  animals  care  to 
eat  them,  though  they  have  their  own  particular  cater- 
pillars. 

Many  plants  are  not  merely  disagreeable,  but  even 
poisonous  to  mammals,  though  birds  may  eat  the  seeds, 
and  insects  the  leaves,  with  impunity;  and  others  again 
are  of  such  a  biting  flavor  as  to  raise  blisters  on  the 
tongue  or  skin.  Some  members  of  the  buttercup  family 
are  of  this  acrid  nature,  and  the  buttercup  itself  is  said  to 
be  avoided  by  cattle;  but  on  the  other  hand,  the  deadly 
nightshade,  which  is  fatal  to  man,  is  eaten  with  impunity 
by  the  rabbit. 

The  Asclepias  gigantea  of  the  desert  is  so  deadly  that 
the  least  drop  of  the  poisonous  milk  contained  in  its  leaves 
and  stem  causes  total  blindness  if  it  touches  the  eye;  and 
even  those  who  cut  the  plant  for  fire-wood  must  beware  of 
so  much  as  touching  their  eyes  afterwards,  since  a  merely 
accidental  rub  may  deprive  them  of  sight. 

One  would  suppose,  therefore,  that  the  Asclepias  was 
so  amply  protected  as  to  have  no  enemy  at  all;  yet  there 
is  one  upon  which  its  deadliness  makes  no  impression 
whatever;  and  this,  the  goat,  devours  it  greedily,  though 
all  other  animals  refuse  and  avoid  it. 

Goats  are  indeed  the  most  omnivorous  and  most 
destructive  of  animals,  and  very  few  plants,  or  even  trees, 
are  safe  from  them.  Neither  the  thorns  of  the  prickly 
pear  nor  the  flinty  "needles"  'of  young  pines  and  flrs 
afford  any  sufficient  protection  against  them ;  and  yet  even 
the  goat  has  its  preferences,  and  is  said  to  refuse  lettuce, 
while  it  will  eat  cabbage. 

Probably  each  plant  has  its  own  appropriate  enemy — 
really  a  friend  to  the  race — whose  office  it  is  to  check  its 


Friends  and  Foes  259 

undue  multiplication.  And  one  reason  why  plants  intro- 
duced into  other  lands  sometimes  run  riot  there,  and  even 
extirpate  the  natives,  is  just  this,  that  they  are  foreigners, 
and  that  there  is  at  first  no  animal  to  keep  them  within 
bounds.  If  there  had  been  some  common  bird  to  eat  the 
seeds  of  the  wild  artichoke  or  "thistle,"  for  instance, 
when  first  it  reached  South  America,  it  could  not  have 
gained  the  upper  hand  so  entirely  as  it  has  done.  At 
present  the  plant  itself  is  eaten  to  some  extent  by  horses 
and  mules,  but  only  when  other  forage  is  scarce,  as  its 
spiny  leaves  are  a  great  protection,  and  make  it  actually 
formidable  to  most  quadrupeds.  Goats  might  manage  it, 
but  otherwise  it  seems  that  birds  are  what  are  wanted  to 
keep  it  in  check.  Eventually,  however,  man  may  prove 
to  be  its  "appropriate  enemy,"  and  will  cut  and  stack  it, 
as  he  has  begun  to  do  with  its  cousin,  the  Scotch  thistle, 
in  Victoria,  which  proves  excellent  winter  food  for  cows, 
when  thus  treated,  as  the  spines  lose  their  stiffness  when 
dried. 

Foreign  plants  are,  however,  sometimes  at  a  disadvan- 
tage when  introduced  into  a  new  country,  as  they  may 
meet  with  enemies  unknown  in  their  native  land,  and 
against  which,  therefore,  they  are  undefended.  But 
generally  speaking,  foreigners  are  much  let  alone  at  first, 
for  most  animals  are  suspicious  of  anything  new  and 
unfamiliar;  and  nearly  all,  especially  of  the  mammalia, 
far  surpass  us  in  keenness  of  scent.  They  "live  in  a 
world  of  odors,"  most  of  them  with  their  noses  near  the 
ground,  always  on  the  qui  vive  to  notice  anything  strange; 
and  generally  speaking,  what  is  new  and  strange  that  they 
mistrust  and  avoid. 

When  they  have  attained  a   fair  size   most   plants  can 


26o  The  Great  World's  Farm 

well  afford  to  have  some  of  their  leaves  eaten;  but  if  no 
blossoms  are  left  the  plant  dies  without  successors,  and 
this,  in  many  cases  at  least,  is  not  to  be  desired.  Accord- 
ingly we  find  that,  as  a  rule,  blossoms  are  avoided  by  all 
animals,  including  even  caterpillars,  which  would  rather 
die  of  hunger  than  eat  the  blossom  of  the  very  plant 
whose  leaves  are  their  favorite  food.  Earwigs,  indeed, 
are  less  particular,  and  are  given  to  biting  dahlias;  and 
whatever  wild  rabbits  may  do,  tame  ones  often  begin  with 
the  blossom  of  poppies  and  succory,  as  if  it  were  a  choice 
morsel. 

Plants  are  protected  against  indiscriminate  consumption 
in  a  variety  of  ways:  by  being  unpleasant  in  flavor  or 
poisonous,  by  the  toughness  and  hardness  of  their  foliage, 
by  prickles  and  by  thorns,  sometimes  of  formidable  size, 
and  by  hairs,  whether  sticky  or  stinging. 

Prickles  and  thorns  are  among  the  most  efficient  guards 
a  plant  can  have,  and  are  often  positively  formidable 
weapons  of  defense.  One  has  only  to  think  of  the  strong, 
stout  thorns  of  the  rose,  and  the  long,  sharp  ones  of  the 
gooseberry-bush,  to  realize  that  it  would  be  dangerous  for 
any  animal  to  attempt  to  make  a  meal  of  them.  The 
sharp  little  prickles  of  the  raspberry,  too,  must  make  it, 
one  would  think,  anything  but  pleasant  eating  to  most 
creatures,  though  donkeys  will  munch  raspberry-canes  as 
well  as  thistles. 

But  small  thorns,  sharply  as  they  can  wound,  are  a 
mere  trifle  compared  with  those  which  protect  many 
foreign  plants  and  trees  until  they  have  grown  beyond  the 
reach  of  cattle.  Even  the  tough  hide  of  the  elephant  is 
not  proof  against  the  "jungle  nail,"  or  "elephant  thorn," 
an    acacia,    whose    lancet-like    spines — which    frequently 


Friends  and  Foes  261 

grow  not  singly,  but  in  branching  clusters— make  any 
forest  where  it  abounds  absolutely  impassable. 

The  buffalo  thorn,  or  bull's  horn  acacia,  is  interesting 
in  another  way.  Its  trunk  and  branches  are  beset  by 
strong  thorns  two  or  three  inches  long  and  as  sharp  as 
needles,  which  grow  in  pairs,  and  are  shaped  just  like 
horns.  But  as  if  this  were  not  enough  to  insure  its 
safety,  the  tree  maintains  as  well  a  standing  army,  which 
keeps  off  all  aggressors,  large  and  small,  at  least  during 
the  wet  season,  for  then  every  thorn  is  tenanted  by  ants, 
which  rush  out  and  sting  severely  any  animal  venturing  to 
touch  the  tree. 

Caterpillars,  which  might  make  their  way  between  the 
thorns  without  injury,  have  no  chance  against  the  ants, 
and  even  their  own  rapacious  relations,  the  leaf-cutting 
ants,  are  completely  baffled. 

The  ants  of  the  buffalo  thorn  are  not  to  be  found  in 
the  forest,  or  indeed  anywhere  except  on  this  particular 
acacia,  which  belongs  especially  to  the  dry  plains  or  savan- 
nahs of  Central  America.  When  the  "horns"  are  first 
put  forth  they  are  filled  with  a  soft,  sweetish  pulp,  which 
the  ants  hollow  out,  burrowing  between  the  partition 
which  separates  them,  and  thus  making  a  single  dwelling 
of  each  pair.  The  thorns  do  not  suffer  in  any  way  from 
this  treatment,  and  continue  to  grow  until  they  have 
reached  their  full  size. 

But  the  ants  do  not  frequent  the  trees  for  the  sake  of 
comfortable  lodgings  merely.  They  want,  and  find,  food 
as  well.  At  the  base  of  each  pair  of  young  leaflets  there 
is  a  gland,  which  contains  a  liquid  something  like  honey; 
and  besides  this,  the  young  leaves  bear  what  are  described 
as  "minute  golden  pears,"  small,   sweet  protuberances, 


262  The  Great  World's  Farm 

which  ripen  in  succession,  and  need  constant  examination. 
These  two  dehcacies,  their  sole  food,  the  ants  are  always 
ready  to  defend,  and  during  the  wet  season  hundreds  of 
them  may  be  seen  running  about  on  the  young  leaves, 
which  are  thus  kept  clear  of  all  enemies  for  some  time 
after  they  unfold. 

A  very  different  ant,  the  parasol,  or  leaf-cutting  ant, 
is  one  of  the  worst  enemies  of  vegetation  in  tropical 
America,  where  it  is  called  the  curse  of  the  country, 
owing  to  the  damage  which  it  inflicts  on  the  crops.  It 
may  be  a  friend  in  disguise  to  the  wild  crops,  by  prevent- 
ing their  too  great  increase,  and  its  services  in  the  past  in 
burrowing  and  tunneling  and  in  adding  to  the  organic 
matter  of  the  soil  must  not  be  forgotten;  but  at  the  present 
day  the  farmer  can  hardly  look  upon  it  as  other  than  an 
enemy.  It  is  the  cultivated  plants  of  foreign  origin  which 
it  especially  attacks,  for  very  many  of  the  natives  are 
protected  against  it  in  one  way  or  other,  while  the  foreign- 
ers are  undefended — a  good  example  of  the  risks  some- 
times run  in  this  way  by  colonists. 

The  Indians  defend  their  trees  by  a  very  simple  device, 
that  of  fastening  thick  wisps  of  grass  with  the  sharp 
points  turned  downwards  round  their  stems.  The  multi- 
tude of  points  quite  baffles  the  ants,  and  prevents  their 
climbing  farther  up.  Orange-growers  plant  their  young 
trees  in  the  center  of  ring-shaped  earthen  vessels,  which 
are  kept  filled  with  water,  and  answer  one  of  the  purposes 
of  the  natural  "basins"  of  the  teasel,  and  other  similar 
plants. 

In  some  parts  of  America  orange-trees  have  run  wild, 
and  have  formed  thickets,  in  spite  of  the  ants;  but  gener- 
ally speaking,    all  the  species  of   the  citron  family — the 


Friends  and  Foes  263 

orange,  lemon,  etc. — except  the  lime,  would  be  very 
quickly  destroyed  if  they  were  left  without  the  help  and 
protection  of  man.  The  lime  has  run  wild,  and  seems  to 
be  less  liked  by  the  ants  than  the  orange  and  lemon,  whose 
leaves  they  *'cut  up  into  sixpences"  when  they  have  the 
opportunity,  leaving  nothing  but  rags  behind  them.  They 
are  terrible  enemies  to  young  plantations,  nurseries,  and 
gardens;  but  they  greatly  fear  the  small  ants  which  pro- 
tect certain  plants. 

The  agricultural  ant  of  Texas  occupies  a  different 
position  from  that  of  the  leaf-cutter,  for  she  is  really  an 
agriculturist  on  her  own  account,  and  the  only  one  in  the 
animal  world,  so  far  as  we  know.  She  is  no  more  an 
enemy  to  vegetation,  therefore,  than  the  farmer  who  cuts 
down  "bush"  that  he  may  grow  wheat,  for  she  does  a 
precisely  similar  thing. 

It  is  unfortunate  for  the  farmer,  of  course,  when  her 
"bush"  chances  to  be  his  corn  or  sweet  potatoes,  which 
she  cuts  down  as  ruthlessly  as  he  does  scrub;  or  when  she 
decides  that  his  young  fruit-trees  must  be  stripped  of  their 
leaves  because  they  keep  off  too  much  of  the  sunshine 
from  her  domain.  But  she  does  not  plunder  his  crops  for 
food,  and  she  does  grow  and  tend  and  reap  crops  of  her 
own  as  regularly  and  carefully  as  he  does  himself. 

For  this  purpose,  at  least  partly,  she  makes  circular 
clearings  some  ten  or  twelve  feet  in  diameter,  sometimes 
in  rough,  wild  pasture,  sometimes  in  the  middle  of  the 
farmer's  fields;  and  she  clears  away  his  cotton  or  corn 
just  as  impartially  as  she  does  the  weeds,  for  to  her  they 
are  weeds.  Considering  her  size,  her  labors  are  truly 
herculean,  for  she  cuts  through,  with  her  teeth,  stems  as 
thick  as  a  thumb;  and  by  dint  of  sawing,  twisting,  pull- 


264  The  Great  World's  Farm 

ing,  biting,  she  clears  everything  away,  no  matter  how 
rank  the  growth.  And  this  is  not  all,  for  the  space  is  not 
only  cleared  once,  but  kept  clear  till  the  "ant-corn"  has 
ripened — a  matter  involving  no  small  labor  where  it  is 
surrounded  by  a  dense  growth  of  weeds  always  ready  to 
encroach. 

The  crop  consists  of  a  tall,  yellowish  grass,  and  not  so 
much  as  a  blade  of  any  other  species  is  allowed  among  it. 
It  ripens  about  the  end  of  June,  when  the  seed  is  cut  from 
the  stalk  and  carefully  stored.  That  which  falls  of  itself 
to  the  ground  is  not  harvested,  and  it  is  probably  from 
this  that  the  next  year's  crop  springs,  though  some  have 
declared  that  the  ants  actually  sow  as  well  as  reap. 
Harvest  over,  the  dry  stubble  is  cut  and  cleared  away, 
and  weeds  are  left  to  grow  as  they  will  during  winter,  the 
work  of  cutting  them  down  beginning  vigorously  again  in 
spring. 

These  ants  live  chiefly  on  grass  seeds,  which  they 
gather  from  a  distance  as  well  as  from  the  home  crop; 
but  though  they  do  not  steal  food  from  the  farmer,  they 
inflict  much  injury  on  his  fields,  and  destroy  many  an  acre 
of  produce,  no  amount  of  plowing  being  sufficient  to  drive 
them  away. 

We  cannot  attempt  any  description  of  the  devastations 
caused  by  locusts,  one  of  whom  is  reported  by  Mahomet 
to  have  remarked,  **We  are  the  army  of  the  great  God; 
we  produce  ninety-nine  eggs.  If  the  hundred  were  com- 
plete, we  should  consume  the  whole  earth  and  all  that  is 
in  it."  Nor  can  we  tell  of  the  ravages  of  the  American 
crickets,  which  eat  up  a  whole  crop  of  maize  in  a  night; 
or  of  the  caterpillars,  which  would  completely  destroy  the 
tobacco  plantations  if  not  constantly  picked  off  leaf  by 


Friends  and  Foes  265 

leaf;  or  of  the  minute  beetles,  whose  grubs,  penetrating 
between  wood  and  bark,  destroyed  in  i;8o  and  the  follow- 
ing years  a  million  fir-trees  in  the  Harz  Mountains  and 
Switzerland,  fifty  thousand  trees,  chiefly  oaks,  more 
recently  in  the  Bois  de  Vincennes,  and  are  causing  avenues 
of  fine  elms  to  disappear  in  the  north  of  France.  Green 
fly,  scale  insects,  slugs,  wireworm,  grubs,  and  the  various 
other  plagues  known  to  the  gardener  and  agriculturist 
must  also  be  passed  over,  and  we  must  go  on  to  consider 
by  what  natural  means  these  various  creatures  are  kept  in 
check  and  prevented  from  becoming  positive  enemies  to 
all  vegetation,  instead  of  merely  thinning  the  ranks,  to  the 
advantage  of  the  survivors. 

For  when  one  reads  of  flights  of  butterflies  which  take 
days  and  weeks  to  pass,  of  armies  of  caterpillars  which 
stop  the  progress  of  railv/ay  trains,  and  of  dense  clouds 
of  locusts  several  miles  long,  it  is  quite  evident  that  unless 
their  increase  were  restricted  by  some  very  eflicient  means 
they  would  all  more  than  justify  the  locust's  boast,  and 
leave  not  so  much  as  a  blade  of  grass. 

Man  is  utterly  unable  to  cope  with  them  by  any  means 
at  his  present  disposal,  and  when  he  interferes  with 
nature's  way  of  keeping  them  within  bounds,  he  learns 
by  hard  experience  his  own  utter  helplessness,  and  often 
not  till  then. 

In  the  Middle  Ages  people  seem  to  have  had  the  feeling 
that  they  ought  to  be  able  to  control  grubs  and  the  like 
by  the  mere  word  of  command,  and  the  chroniclers  of  the 
time  often  give  reports  of  the  lawsuits  instituted  against 
these  creatures.  In  1479,  for  example,  the  canton  of 
Berne  was  troubled  with  such  an  overwhelming  plague  of 
grubs  that   the  council  petitioned  the  archbishop  of  Lau- 


266  The  Great  World's  Farm 

sanne  to  banish  them,  and  the  priests  were  authorized  by 
him  to  do  so.  In  accordance  with  the  usual  custom  on 
these  occasions,  advocates  were  appointed  for  both 
parties — the  grubs  and  the  people.  A  written  summons 
was  issued;  the  grubs  were  cited  to  appear,  and  some 
were  brought  into  court ;  but  they  were  not  fairly  treated, 
as  the  advocate  assigned  to  them  was  no  longer  living,  and 
judgment  was  given  against  them  in  these  terms:  **We, 
the  archbishop  of  Lausanne,  condemn  and  excommunicate 
ye  obnoxious  worms  and  grubs,  that  nothing  shall  be  left 
of  ye  except  such  parts  as  can  be  useful  to  man." 

No  steps  seem  to  have  been  taken,  however,  to  give 
effect  to  the  sentence,  and  the  grubs  obstinately  ignored  it. 

But  if  the  council  could  have  imported  a  few  hundreds 
of  small  birds,  they  would  most  likely  have  been  quickly 
rid  of  the  plague;  for  these,  and  these  alone,  are  the 
natural  and  most  effectual  provision  for  keeping  the  num- 
bers of  grubs,  caterpillars,  and  the  like  within  their  proper 
limits. 

QUESTIONS  FOR  REVIEW 

1.  Show  how  different  plants  have  their  appropriate 
enemies. 

2.  What  advantages  have  foreign  plants? 

3.  In  what  different  ways  do  plants  protect  themselves? 

4.  What  peculiarity  has  the  bull's  horn  acacia? 

5.  By  what  means  are  ants  prevented  from  injuring  various 
kinds  of  vegetation? 

6.  Describe  the  habits  of  the  agricultural  ant. 

7.  What  surprising  instances  can  be  given  of  the  ravages 
of  insects? 


CHAPTER    XXI 

NATURE'S  MILITIA 

"If  nature's  militia,  the  army  of  birds,  be  killed,  it  will 
be  impossible  to  find  a  substitute  for  their  faithful  guar- 
dianship." 

"Birds  are  nature's  soldiers,  and  keep  in  subjection 
the  inferior  animals.  Their  other  uses  are  scarcely  worthy 
of  notice  compared  with  their  labors  in  the  destruction  of 
insects." 

Wise  words,  which  cannot  be  too  often  insisted  on; 
for  though  we  are  beginning  to  wake  up  to  the  immense 
value  of  the  feathered  tribes  as  guardians  of  our  fields,  we 
are  still  only  beginning;  and  unfortunately,  farmers  and 
gardeners,  the  very  persons  most  interested,  are  precisely 
those  whom  it  is  most  difficult  to  arouse. 

They  know  well  enough,  of  course,  that  insects,  gen- 
erally speaking,  are  their  enemies;  but  they  do  not  yet 
recognize,  as  they  ought,  that  the  birds  are  their  friends, 
who,  if  only  let  alone,  would  save  the  crops  from  these 
marauders. 

A  plague  of  grubs  finds  us,  in  fact,  just  as  helpless  as 
our  forefathers  in  the  Middle  Ages,  and  almost  more  hope- 
less, for  we  no  longer  believe  in  trying  to  "banish"  our 
enemies,  and  we  have  not  yet  discovered  any  more  effec- 
tual means  of  dealing  with  them.  When  the  infliction 
comes,  we  talk  mysteriously  of  "blight"  and  "weather"; 
and  it  seldom  occurs  to  us  to  connect  the  increase  of  grubs 

267 


268  The  Great  World's  Farm 

with  the  destruction  of  birds,  even  though  we  must  know, 
as  a  matter  of  fact,  that  the  latter  Hve  mainly  upon  the 
former,  and  that  therefore  for  every  bird  killed,  so  many 
grubs  must  be  left  alive. 

It  is  now  some  thirty  years  since  piteous  complaints 
were  rife  in  Germany  and  Switzerland  of  the  alarming 
increase  in  the  number  of  destructive  insects,  which  made 
their  appearance  in  overwhelming  swarms,  and  inflicted 
the  greatest  injury  on  the  fields.  And  at  last  it  occurred 
to  the  authorities  that  insects  had  multiplied  because  birds 
had  to  so  large  an  extent  vanished.  The  "militia"  had, 
in  fact,  been  either  killed  off  or  driven  away;  they  had 
been  destroyed  in  the  most  insane  manner,  in  ignorance 
and  sheer  wantonness ;  and  also  they  had  been  *  *  improved' ' 
away  by  the  spread  of  agriculture.  In  whatsoever  way  it 
had  come  to  pass,  the  result  was  the  same — there  were 
fewer  birds,  there  were  more  grubs;  and  as  the  latter 
increase  much  more  rapidly  than  the  former,  the  prospect 
was  a  dismal  one.     The  land  was  being  devoured. 

And  it  was  devoured,  partly  at  least,  because  more  had 
been  taken  into  cultivation.  For  woods  and  thickets  and 
groups  of  trees  had  been  cut  down  to  make  way  for  fields; 
and  land  being  precious,  hedges  were  considered  an 
unnecessary  extravagance.  There  are,  of  course,  still 
extensive  woods  and  forests  in  Germany,  but  one  may 
travel  many  a  long  mile  without  seeing  any  of  the  hedge- 
rows with  which  he  is  familiar  in  England.  The  fields 
are  for  the  most  part  one  large  expanse,  without  any 
bordering  of  trees  or  bushes. 

But  it  is  quite  possible  to  be  too  thrifty.  If  every  foot 
of  land  is  occupied  by  crops,  where  are  the  birds  to  build 
their  nests.?     Most  of  them  need  more  shelter  than  is  to 


Nature's  Militia  269 

be  found  upon  the  ground,  and  if  they  cannot  find  it  in  one 
place  they  are  obhged  to  look  for  it  in  another.  If  the 
farmer  will  not  spare  them  a  few  trees  and  bashes,  they 
are  compelled  to  desert  his  fields  and  leave  them  unpro- 
tected. 

But  this  is  not  all.  Grubs  as  well  as  birds  find 
shelter  in  the  hedges;  and  not  only  shelter,  but  food. 
When  the  birds  are  driven  away,  therefore,  the  grubs  are 
driven  away,  too;  but,  alas!  while  the  birds  migrate  to  a 
distance,  the  grubs  are  only  driven  out  of  the  bushes  and 
hedge-plants,  where  they  are  comparatively  harmless,  into 
fields,  orchards,  and  gardens,  where,  in  the  absence  of 
the  "militia,"  they  run  riot  as  they  will. 
We  see,  indeed,  the 

"  Hedges  all  alive 
With  birds  and  gnats,  and  large  white  butterflies, 
Which  look  as  if  the  May-flower  had  caught  Hfe, 
And  palpitated  forth  upon  the  wind." 

We  see;  but  perhaps  we  hardly  realize  that  if  the 
hedge  be  cut  down  its  population  will  find  quarters  else- 
where; and  that  while  the  birds  betake  themselves  to  the 
nearest  thicket,  perhaps  some  distance  off,  the  butterflies 
and  moths  will  simply  flit  a  few  yards,  many  of  them 
being  quite  content  to  supply  their  offspring  with  culti- 
vated plants  when  they  cannot  get  wild  ones.  Somewhere 
or  other  they  must  and  will  lay  their  eggs — if  not  in  the 
hedgerow,  then  in  the  garden;  and  the  grub  of  the  white 
butterfly  is,  as  we  all  know,  able  to  make  quite  a  decent 
living  upon  cabbage-leaves. 

But  this  was  not  all,  or  nearly  all.  Not  only  had  the 
grubs  been  driven  into  the  fields,  and  the  birds  driven  out 
of  them,  but  the  latter  had  been  killed  wholesale.     Gov- 


270  The  Great  World's  Farm 

ernment  keepers  were  actually  under  orders  to  destroy  the 
woodpeckers,  whose  special  office  it  is  to  rid  the  trees  of 
beetle-grubs,  and  the  cuckoos,  which  devour  the  hairy 
caterpillars  which  no  other  birds  will  touch,  and  so  on. 

And  the  Germans  have  not  been  the  only,  or  even  the 
chief,  offenders.  They  have  killed  their  own  birds,  and 
have  suffered  for  it.  But  the  Italians  have  done  worse; 
for  they  have  waged  deadly  war  upon  the  birds  which  are 
the  common  property  of  Europe.  They  have  a  perfect 
mania  for  slaughtering  small,  insect-eating  birds,  and 
unhappily  they  have  special  opportunities  of  gratifying  it, 
as  large  flocks  of  migrants  pass  through  this,  to  them 
inhospitable,  land  every  year  on  their  way  to  and  from  the 
south.  Considering  the  way  in  which  they  were  received, 
one  wonders  why  they  did  not  choose  some  other  route; 
but  the  force  of  habit  seems  to  be  too  strong  for  them, 
and  their  ranks  have  been  thinned  year  after  year  in  the 
most  fatal  manner.  Not  even  the  swallows  were  allowed 
to  pass  unmolested;  for  to  catch  them,  by  floating  hooks 
baited  with  flies  in  the  air,  seems  to  have  been  considered 
a  particularly  fascinating  pastime. 

For  months  the  chief  delight  of  the  population  was  in 
catching  birds,  and  several  million  were  killed  regularly 
each  autumn  in  the  neighborhood  of  Verona  alone.  Larks 
are  among  the  most  useful  of  the  insect-eating  birds,  and 
so  entirely  harmless  that  even  the  farmer  has  no  fault  to 
find  with  them.  Yet  neither  their  usefulness  nor  their 
harmlessness  were  sufficient  to  save  them  from  persecution. 
Unluckily  for  themselves,  and  we  may  add,  for  Europe, 
they  had  chosen  Sicily  as  one  of  the  places  at  which  to 
break  their  journey,  and  they  could  hardly  have  done 
worse.     The  Sicilians  knew  when  to  expect  them,  for  they 


Nature's  Militia  271 

came  regularly  every  autumn,  nearly  a  million  arriving 
daily  for  ten  days,  and  they  gave  them  a  warm,  reception. 
Hundreds  of  the  population  v^rent  out  to  meet  them, 
armed  with  guns,  and  there  was  a  regular  battue.  How 
many  »vere  slain  history  does  not  say,  but  the  numbers 
must  have  been  very  great.  They  did  not  die  unavenged, 
however;  for  every  lark  killed  left  so  many  more  insects 
to  rav  ige  the  crops;  and  when  people  woke  up  enough  to 
put  tv  o  and  two  together,  and  to  connect  the  plagues  of 
insect .  with  the  destruction  of  the  "militia"  which  should 
have  :ept  them  under,  measures  were  taken  to  check  the 
persecution. 

To  some  extent  birds  are  now  protected  in  Europe; 
but  we  do  not  seem  to  have  learned  our  lesson  even  yet,  for 
a  cry  that  the  birds  are  being  exterminated  is  now  making 
itself  heard  in  Asia,  Africa,  and  America.  The  war 
carried  on  against  them  in  India  is  already  having  very 
serious  results;  the  swamps  and  marshes  of  Florida  are 
being  depopulated;  Guinea  is  being  despoiled  of  its  birds 
of  paradise,  and  birds  of  bright  plumage  are  becoming 
more  and  more  rare  everywhere  all  over  the  world. 

And  why  all  this  slaughter?  Not  because  there  is  a 
famine  in  the  land,  and  the  birds  are  needed  for  food;  not 
even  for  the  sake  of  "sport";  but  because  the  fashionable 
women  of  Paris,  London,  and  Vienna  require  the  sacrifice 
of  at  least  thirty  million  birds  every  year,  that  they  may 
decorate  themselves  with  feathers. 

In  India,  which  furnishes  hundreds  of  thousands  of 
skins  every  year,  insect  life  is  rampant  beyond  anything 
that  we  have  experience  of,  and  is  "only  kept  within 
bounds  by  the  utmost  effort  of  all  the  checks  provided  by 
nature."     The  "patient,  unpaid  labor  of  the  useful  small 


272  The  Great  World's  Farm 

birds"  is  the  one  only  remedy  for  the  insect  epidemics  to 
which  the  empire  is  hable,  and  it  is  sheer  madness  to  allow 
them  to  be  killed  off. 

We  must  hope  that  the  "Indian  Wild  Birds'  Protection 
Act"  will  at  least  check  the  slaughter,  for  if  it  be  allowed 
to  go  on,  it  can  have  but  one  result,  and  the  birds  will  be 
avenged  here,  as  they  have  already  been  in  Europe. 
When  once  they  are  gone,  no  artificial  substitutes  can  by 
any  possibility  make  up  for  them.  One  may  syringe  the 
fruit-trees,  cover  the  gooseberry-bushes  with  road-dust, 
pay  regiments  of  school-children  to  gather  grubs  by  the 
quart,  try  in  fact  all  the  various  expedients  which  have 
ever  been  resorted  to,  and  yet  find  in  the  end  that  it  is 
simply  impossible  to  overtake  the  damage  caused  by  the 
absence  of  the  birds,  with  their  marvellously  keen  sight 
and  extraordinary  appetites. 

Let  us  consider  for  a  moment  one  single  fact.  Mr. 
Darwin  found  that  scarcely  more  than  a  sixth  part  of  his 
seedlings  survived  the  attacks  of  slugs,  snails,  and  insects. 
But  what  does  this  mean.?  Only  this,  that  if  the  numbers 
of  the  enemy  had  been  increased  by  so  much  as  a  sixth, 
there  would  have  been  no  seedlings  left  alive  at  all. 

Take,  for  example,  the  common  house-fly,  one  of  which 
is  said  to  have  twenty-one  million  descendants  in  the 
course  of  a  single  summer,  or  would  have,  if  all  were 
allowed  to  live.  That  we  do  not  have  a  yearly  plague  of 
flies  is  due  solely  to  the  vigilance  of  the  birds. 

And  what  quantities  they  devour!  for  their  digestion 
is  very  rapid,  and  whereas  human  beings  require  only  a 
few  ounces  of  dry  food  a  day,  they  swallow  a  quantity 
which  is  equal  to  their  own  weight.  Think  of  it!  the 
weight  of  a  bird  in  insects;  green  flies,  for  instance. 


Nature's  Militia  273 

One  redstart,  kept  in  a  room,  has  been  known  to  eat 
six  hundred  flies  in  an  hour;  and  one  blackcap  has  cleared 
about  two  thousand  greenflies  from  the  rose-trees  in  a 
greenhouse  in  the  course  of  a  few  hours. 

The  titmouse  is  another  most  active  little  bird,  con- 
stantly engaged  in  the  hunt  for  food,  creeping  into  rolled-up 
leaves,  and  devouring  by  the  thousand  eggs  which  would 
produce  many  more  hairy  caterpillars  than  the  cuckoos 
could  dispose  of. 

The  wren,  like  the  titmouse,  is  perpetually  eating,  and 
feeds  her  young  thirty-six  times  in  an  hour;  the  cuckoo, 
too,  eats  all  day  long,  every  five  minutes  or  so,  and 
devours  about  one  hundred  and  seventy  good-sized  cater- 
pillars in  the  day;  and  as  each  of  these  caterpillars,  if 
allowed  to  reach  the  butterfly  state,  might  lay  some  five 
hundred  eggs,  every  cuckoo  rids  us  of  a  possible  eighty- 
five  thousand  odd  caterpillars  daily! 

And  the  work  goes  on  vigorously  in  winter,  as  well  as 
in  spring  and  in  summer,  for  with  all  the  vigilance  of  the 
birds,  caterpillars  and  grubs  innumerable  escape  and  pass 
into  the  chrysalis  state,  which  they  spend — as  much  of  it 
as  they  are  allowed — in  cracks  and  crannies,  in  sheltered 
nooks,  on  twigs  and  trunks  of  trees,  on  palings  and  walls, 
and  in  the  ground.  These  supply  food  to  the  many  insect- 
eating  birds  which  do  not  migrate;  and  but  for  the  unceas- 
ing labors  of  these  stay-at-homes  we  should  be  overrun 
with  insects  in  the  spring,  in  spite  of  all  that  is  done  in 
the  summer;  for  each  chrysahs  devoured  saves  us  from 
some  hundreds  of  grubs  or  caterpillars  later  on. 

If  any  one  needs  proof  of  what  would  certainly  follow 
the  extermination  of  the  birds,  he  need  only  look  at  the 
island  of  Jamaica,  where  they  are  at  present  very  scarce. 


274  The  Great  World's  Farm 

having  been  killed  off,  chiefly  to  adorn  women's  bonnets. 
It  must  be  remembered,  too,  that  while  birds  multiply 
only  by  tens,  insects  increase  by  hundreds,  by  thousands, 
and  by  tens  of  thousands,  in  a  single  season,  so  that 
although  the  birds  are  now  protected  in  Jamaica  it  will  be 
long  before  the  loss  is  made  good.  Meantime  they  are 
terribly  avenged;  for  the  island  suffers  from  a  disgusting 
and  grievous  plague  of  ticks  imported  with  cattle,  which 
swarm  upon  every  leaf  and  blade  of  grass,  except  on  the 
higher  hills. 

To  make  matters  worse,  too,  the  mongoose  was  im- 
ported a  few  years  ago,  and  like  sundry  other  importations, 
has  proved  a  dismal  failure.  The  idea  was  that  it  would 
kill  off  the  rats  which  so  swarmed  in  the  sugar-plantations 
as  to  be  a  great  nuisance  to  the  planters.  And  the  mon- 
goose began  well;  but  when  its  numbers  had  increased,  as 
they  did  enormously,  it  began  to  vary  its  diet  of  rats  by 
eating  the  eggs  of  such  birds  as  build  on  the  ground,  and 
then  it  v/ent  on  to  eat  the  birds  themselves,  and  even 
poultry,  besides  killing  off  all  the  lizards  and  snakes, 
which  were  not  only  quite  harmless,  but  most  useful  as 
insect-eaters.  In  one  way  and  another,  the  ticks  were 
thus  delivered  from  their  natural  enemies,  and  now  have 
things  pretty  much  their  own  way,  and  seem  likely  to 
have  for  some  time  to  come. 

However,  there  are  probably  few  people  in  the  present 
day  who  would  seriously  dispute  the  value  of  such  birds 
as  live  upon  insects  only.  It  is  when  we  come  to  mixed 
feeders,  such  as  the  sparrow  and  the  crow,  that  opinions 
are  divided. 

A  fierce  battle  rages  round  the  sparrow.  He  is  accused 
of  stealing  corn  and   fruit,  and  of  heartlessly  destroying 


Nature's  Militia  ay^ 

crocuses  for  the  sake  of  the  unformed  seeds.  In  some 
districts  he  is  persecuted  without  mercy  and  leads  the  hfe 
of  an  outlaw.  Sparrow  clubs,  encouraged  by  the  farmers, 
kill  him  by  the  thousand  and  destroy  his  nests. 

That  he  is  mischievous  no  one  can  deny,  and  that  he 
sometimes  does  serious  damage  must  be  admitted  even  by 
his  warmest  admirers.  But  if  we  cannot  have  our  crops 
without  paying  toll  upon  them,  it  seems  better  to  share 
with  the  sparrow  than  lose  all  to  the  grub — the  only 
choice,  according  to  some,  which  lies  before  us. 

The  sparrow's  friends,  the  naturalists,  say  that  each 
sparrow  actually  saves  a  bushel  of  corn,  for  he  himself 
lives  for  nine  months  of  the  year  almost  entirely  on  grubs, 
while  his  family  eat  absolutely  nothing  but  insect  food  as 
long  as  they  remain  in  the  nest.  One  pair  of  sparrows, 
it  is  said,  take  four  thousand  three  hundred  grubs  or  other 
insects  to  their  young  in  the  course  of  a  week;  and  that 
they  are  the  deadly  enemies  of  the  cockchafers,  which 
have  done  a  million  pounds'  worth  of  damage  to  the  crops 
in  Normandy,  is  evident,  for  the  wing-cases  of  seven  hun- 
dred cockchafers  have  been  found  under  a  single  nest. 

Finally,  we  are  told  that  caterpillars  to  the  number  of 
3 54. 3 75^000,000  are  eaten  by  sparrows  every  year,  and 
that  while  we  see  the  damage  which  the  sparrow  does 
during  three  months  of  the  year,  we  do  not  see  how  hard 
he  works  for  us  during  the  other  nine,  or  what  far  greater 
damage  he  averts  from  us.  We  grudge  his  wages,  in  fact, 
simply  because  we  do  not  understand  how  vast  are  his 
services. 

But  a  few  facts  are  worth  many  arguments.  Let  us  see 
what  has  followed  the  expulsion  of  the  sparrow  in  one  or 
two  cases.     Frederick   the  Great  of   Prussia  wag^ed  war 


276  The  Great  World's  Farm 

against  the  sparrow,  and — he  was  defeated,  ignominiously 
defeated,  and  he  had  the  good  sense  to  own  it.  The  king 
hked  cherries,  and  the  birds  hked  them,  too;  and  he  gave 
orders  that  the  sparrows  should  be  driven  away,  extermi- 
nated, got  rid  of.  And  he  was  so  well  obeyed,  that  in 
two  years'  time  there  was  not  a  sparrow  left  in  the  neigh- 
borhood. So  far  he  was  the  victor,  for  he  had  certainly 
vanquished  the  birds;  but  he  had  overreached  himself,  for 
instead  of  having  more  cherries  he  had  none ! 

There  were  no  cherries  at  all  that  year;  worse  still, 
there  was  no  fruit  of  any  kind,  but  in  its  stead  a  hideous 
crop  of  caterpillars,  which  had  stripped  the  trees  of  their 
leaves.  Other  birds  besides  sparrows,  of  course,  eat 
caterpillars,  but  the  means  used  to  get  rid  of  the  sparrows 
had  frightened  these  others  away  also.  The  orchards  had 
been  deprived  of  their  guardians,  and  the  enemy  had  taken 
possession,  and  before  matters  could  be  set  right  sparrows 
had  to  be  imported,  at  considerable  expense;  for  they 
would  never,  it  is  said,  have  returned  of  their  own  accord 
as  they  are  not  given  to  wandering. 

Pigeons  are  the  only  birds  which  live  on  nothing  but 
vegetable  food;  yet  the  wood-pigeon  is  now  recognized 
as  such  a  valuable  servant  in  Belgium,  from  its  habit  of 
eating  the  seeds  of  the  poppy,  spurge,  and  others  which 
no  domestic  animal  can  touch,  that  it  is  strictly  preserved. 
Where  such  seeds  are  not  to  be  had  in  sufficient  quantities, 
no  doubt  the  pigeon  makes  up  for  it  by  stealing  peas  and 
corn,  but  the  Belgians  seem  to  have  made  up  their  minds 
that  it  is  better  to  run  the  risk  of  having  to  pay  occasional 
toll  to  the  pigeons  than  to  have  their  crops  choked  with 
weeds. 

A  few  words  as  to  what  in  temperate  latitudes  may  be 


Nature's  Militia  277 

regarded,  perhaps,  as  the  farmer's  three  worst  enemies — 
cockchafers,  daddy-long-legs,  and  click-beetles  or  skip- 
jacks. It  is  in  the  grub  state  that  most  insects  are  chiefly 
mischievous,  for  this  is  their  grand  eating-time;  eating  is 
then  their  sole  business,  and  they  eat  for  their  whole  lives. 
For  when  they  get  their  wings  they  usually  want  so  little 
food,  and  that  of  such  a  kind  that  no  one  can  grudge  it 
them.  A  caterpillar  eats  leaves,  for  instance,  and  devours 
them  greedily,  whereas  a  butterfly  takes  but  a  sip  of  nec- 
tar, the  loss  of  which  is  no  injury  to  even  the  most  delicate 
flower.  Yet  as  the  winged  insects  lay  multitudes  of  eggs, 
they  cannot  be  called  harmless,  and  some  few  of  them 
even  do  a  good  deal  of  eating  on  their  own  account. 
Cockchafers,  for  example,  eat  leaves,  and  sometimes  strip 
whole  woods,  while  their  grubs  devour  roots.  Daddy- 
long-leg  grubs  (turnip-fly)  are  equally  destructive,  and  so 
terribly  hardy  that  they  thoroughly  deserve  their  name 
of  leather-jackets,  for  they  are  very  little  affected  by 
weather,  and  may  be  frozen  stiff,  or  lie  under  water  for 
a  couple  of  days,  and  yet  be  just  as  lively  as  ever  after- 
wards. Insects,  indeed,  often  take  a  great  deal  of  killing, 
and  will  live  through  frosts,  especially  in  the  chrysalis- 
state,  when  the  poor  birds  perish  by  hundreds. 

As  for  the  grub  of  the  click-beetle,  its  very  name  is 
enough  to  make  a  farmer  shudder,  for,  as  the  wire-worm, 
it  is  only  too  well  known.  For  five  whole  years  it  remains 
a  grub,  eating  all  the  time.  And  it  will  eat  almost  any- 
thing in  the  way  of  vegetable  food,  turnips  as  well  as 
sprouting  corn,  or  hops,  and  grass-roots  as  well  as  any  of 
these.  Where  the  young  corn  is  strong,  it  will  sometimes 
recover  from  having  its  first  shoot  eaten  off"  just  below  the 
ground,  and  will  even  send  up  two  or  three  shoots  instead 


278  The  Great  World's  Farm 

of  one;  but  when  the  plants  are  weak,  as  they  often  are 
on  hght,  chalky  soil,  there  the  wire-worm  destroys  some- 
times the  half,  and  occasionally  the  whole,  of  a  crop. 

To  help  him  in  the  perpetual  war  which  has  to  be 
waged  with  these  three  special  foes,  the  farmer  has 
friends — the  sparrow  again,  and  the  crow,  jackdaw,  mag- 
pie, jay,  all  the  smaller  birds  of  prey,  in  fact,  and  many 
of  the  larger;  and  besides  these,  he  has  the  stoat,  weasel, 
mole,  and  hedgehog,  which  last,  though  much  persecuted, 
is  most  useful,  and  quite  inoffensive. 

The  battle  about  the  crow  is  only  less  fierce  than  that 
about  the  sparrow,  but  while  it  is  no  doubt  true  that  he 
does  uproot  some  plants  in  his  search  for  grubs,  that  he 
does  steal  a  little  corn,  and  that,  when  insects  are  scarce,  or 
crows  too  many,  he  even  attacks  the  crops,  still,  where 
crows  are  poisoned,  wire-worm  increases  and  crops  fail. 
One  crow  will  have  as  many  as  three  dozen  daddy-grubs 
or  click-beetles  in  its  crop  at  once,  and  the  birds  go  over 
the  ground  yard  by  yard  in  the  most  systematic  manner, 
working  from  early  dawn  till  evening,  each  bird  catching, 
it  is  said,  at  least  fifty  wire-worms  in  the  day. 

In  some  parts  of  the  country  the  crows  are  often  joined 
at  their  work  in  the  furrows  by  large  flocks  of  gulls,  tit- 
mice, and  others,  which  appear  when  plowing  begins,  and 
go  away  when  the  furrows  are  cleared,  without  taking  any 
pay  from  the  farmer,  except  in  the  shape  of  the  insect 
food  which  he  is  glad  to  be  rid  of. 

Other  very  useful  birds,  which  must  be  passed  over 
with  a  mere  mention,  are  the  various  species  of  plover, 
the  partridge,  and  the  pheasant — a  couple  of  which  will 
eat  fifteen  hundred  wire-worms  at  a  meal — the  thrush  and 
the  landrail,  both  of  which  clear  the  fields  of  snails  and 


i 


Nature's  Militia  279 

slugs,  and  the  swallow,  martin,  and  swift,  without  whom 
the  air  would  be  so  choked  with  flies  as  to  be  simply 
unbreathable. 

So  much,  then,  for  the  services,  the  incalculable  and 
indispensable  services,  of  the  ''militia."  We  have  seen 
something  of  these,  and  we  have  seen,  too,  how  surely 
punishment  has  followed  where  the  birds  have  been  exter- 
minated; but  there  is  a  word  or  two  to  be  said  on  the 
other  side  of  the  question. 

It  is  very  rash  for  man  to  interfere  with  nature  by 
exterminating  any  one  class  of  the  laborers  employed, 
whether  in  the  tilling  or  in  the  protection  of  the  fields, 
cultivated  or  uncultivated;  but  at  the  same  time,  it  is 
hardly  less  rash  for  him  to  interfere  in  the  other  direction, 
and  to  encourage  these  same  laborers  overmuch;  or  even, 
because  they  are  found  useful  in  one  part  of  the  world,  to 
conclude  hastily  that  they  must  be  equally  useful  in  another. 

Thistles  do  not  overwhelm  us  and  swamp  other  vege- 
tation in  Europe;  but  he  was  a  very  rash  man  who 
imported  a  sack  of  thistle-seed  into  South  America  and 
scattered  it  broadcast  about  Valparaiso,  with  an  idea  of 
providing  useful  fodder  for  cattle!  The  thistle  took  to 
the  soil  and  climate  amazingly,  and  having  nothing  to 
check  its  increase,  as  it  has  at  home,  quickly  spread  over 
large  tracts  of  country,  to  the  great  inconvenience  of  the 
cultivators. 

Then,  some  one  may  be  inclined  to  say,  why  not  import 
birds  to  eat  the  seed.?  But  things  in  nature  are  so  exactly 
balanced  that  even  this  step  would  probably  be  found  to 
have  its  disadvantages,  and  possibly  the  birds  might  turn 
out  to  be  even  worse  than  the  thistles.  The  sparrows 
imported  into  the  United  States,  for  instance,  and  at  first 


2  8o  The  Great  World's  Farm 

petted  and  made  much  of,  have  so  thriven  and  multipUed 
that  they  are  now  a  pest,  and  generally  hated.  But  the 
mischief  is  done,  and  is  not  to  be  so  easily  undone.  They, 
like  the  thistles,  have  had  things  their  own  way,  for  as 
there  were  no  sparrows  in  these  parts  before,  naturally  no 
special  checks  to  their  undue  multiplication  had  been 
provided. 

The  natural  checks  provided  for  keeping  the  small  birds 
in  their  proper  place  are  the  birds  of  prey;  and  these — 
many  of  the  larger,  and  all  the  smaller — not  only  kill  small 
birds  for  their  own  eating,  but  feed  their  young  entirely 
upon  beetles,  grubs,  caterpillars,  flies,  slugs,  snails,  and 
the  various  insects  which  attack  the  green  things.  Many 
of  them,  too,  hunt  by  night,  and  so  destroy  the  night- 
flying  moths  and  beetles  which  escape  other  birds. 

Yet  birds  of  prey,  especially  owls  and  hawks,  are 
relentlessly  persecuted  by  farmers  and  keepers,  because 
they  occasionally  steal  a  young  chicken,  or — more  heinous 
offense  still — young  pheasants  and  partridges,  and  per- 
haps yet  more  often  they  are  killed  because  it  is  the 
fashion  to  kill  them. 

But  even  owls  and  hawks  have  their  avengers.  Spar- 
rows, multiplied  to  excess,  take  to  thieving,  and  commit 
great  depredations  in  the  fields;  and  still  worse  are  the 
plagues  of  mice,  which  mar  the  land^ 

In  Scotland  and  the  north  of  England  there  has  been  a 
great  outcry  of  late  against  the  swarms  of  mice  and  rats 
which  waste  the  fields  and  rob  the  barns,  doing  far  more 
damage  than  the  sparrows.  But  why  this  increase  in 
sparrows  and  mice?  Because  the  owls,  hawks,  stoats, 
and  weasels  have  been  killed  off.  Just  that,  and  nothing 
else. 


LONG-EARED  OWL  BKINGINC  FIELD-MICE  To  HER  VOL'NC. 


Nature's  Militia  2X1 

Owls  are  the  very  best  mousers  possible — better  than 
the  best  cats.  One  pair  of  owls  have  been  seen  to  take 
as  many  as  eleven  mice  to  their  nest  in  the  course  of  a 
single  evening.  Ravens,  crows,  hawks,  magpies,  and  jays 
all  hunt  mice,  as  well  as  cockchafers  and  other  insects,  as 
already  said;  and  the  young  of  the  brown  owl  are  fed 
with  anything,  from  snails  even  to  kittens  and  puppies. 
But  the  young  of  the  barn-owl  require  a  steady  supply  of 
fresh  mice,  and  she  herself  makes  mice  almost  her  sole 
diet,  so  that  she  benefits  not  only  corn  but  clover.  For 
if  it  is  true  that  the  crop  of  clover-seed  depends  to  a  great 
extent  upon  the  number  of  cats  in  the  neighborhood,  surely 
the  presence  or  absence  of  those  grand  mousers,  the  owls, 
must  make  at  least  as  much  difference  to  it.  For  mice 
are  very  much  addicted  to  eating  humble-bees,  as  well  as 
corn;  and  as  the  common  purple  clover  is  fertilized  by 
humble-bees  only,  there  can  be  no  seed  where  humble- 
bees  are  wanting,  which  they  certainly  would  be  if  mice 
were  allowed  to  multiply  unchecked. 

In  America,  birds  of  prey  are  comparatively  rare;  not 
because  they  have  been  killed  off,  as  in  England,  but 
because  nature  had  not  provided  them— a  very  different 
matter.  But  now  that  the  English  sparrow  has  made 
himself  unpleasantly  obtrusive,  hawks  are  being  imported 
as  the  only  likely  means  of  quelling  him.  Why  hawks 
instead  of  owls  is  not  evident,  but  it  will  be  interesting  to 
watch  the  result  of  this  second  experiment;  for  if  the 
hawks  in  their  turn  should  increase  to  excess  they  might 
prove  even  worse  than  sparrows. 

In  some  parts  of  the  world  the  balance  of  animal  life 
established  by  nature  is  very  curious,  and  any  interference 
with  it  is  attended  by  danger.     In  some  districts  in  India, 


282 


The  Great  World's  Farm 


for  instance,  the  tiger  is  as  useful  to  the  farmer  as  owl 
and  hawk  are  here.  If  he  kills  off  the  tigers,  as  his  Eng- 
lish brother  kills  the  birds  of  prey,  then  the  deer  multiply 
and  eat  his  crops;  and  on  the  other  hand,  if  he  kills  off 
the  deer,  the  tigers  kill  him,  for  even  a  tiger  must  live! 
so  that  on  the  whole  he  finds  it  better  not  to  interfere. 

Insects  are,  as  a  whole,  such  enemies  of  vegetation 
that  we  are  apt  to  condemn  them  in  a  body.  Yet  besides 
the  many  which  convey  pollen  there  are  a  few  others 
which  deserve  honorable  mention,  and  even  the  name  of 
friends.  These  few  are  positive  benefactors,  for  they 
leave  the  green  things  alone  themselves  and  prey  upon 
other  mischievous  insects. 

Among  these  insect-friends  is  the  lady-bird,  to  whom, 
as  an  American  writer  says,  'Sve  should  take  off  our 
hats,"  for  it  destroys  those  terrible  pests,  thrips  and 
greenflies. 

Wasps  carry  off  flies  and  caterpillars  to  feed  their 
young  grubs;  and  some  species  of  ichneumon-fly  deposit 
their  eggs  in  the  chrysalides  of  moths  and  butterflies,  as 
weU  as  in  grubs  and  caterpillars,  thereby  killing  them. 
But  of  all  insects,  perhaps  some  of  the  beetles  are  the 
most  useful,  for  both  in  the  grub  and  in  the  winged  state, 
they  catch  and  devour  living  prey. 

To  sum  up:  without  insects  many  plants  would  be 
unable  to  produce  seed,  and  so  must  in  time  die  out; 
without  the  small  birds,  insects  would  increase  so  much 
that  all  green  things  would  be  destroyed;  and  without  the 
birds  of  prey  to  keep  the  number  of  small  birds  within 
bounds,  not  only  would  farming  be  quite  impossible,  but 
wild  plants  would  also  suffer;  for  when  the  insects  were 


Nature's  Militia  og^ 

devoured,  or  even  very  greatly  reduced  in  numbers,  the 
plants  dependent  upon  them  for  help  would  be  seedless, 
and  the  remainder  would  be  so  plundered  of  their  seed  by 
flocks  of  hungry  birds,  that  little  would  be  left  for  sowing. 
Both  insects  and  birds,  then,  are  the  enemies  of  vege- 
tation when  their  numbers  are  multiplied  to  excess;  but 
without  them,  there  would  be  no  vegetation  at  all. 


QUESTIONS  FOR  REVIEW 

1.  Why  do  insects  increase  when  land  is  over-cultivated? 

2.  Describe  the  destruction  of  birds  in  Italy. 

3.  How  is  the  destruction  of  birds  being  felt  in  other  places 
also? 

4.  Give  illustrations  of  the  extent  to  which  birds  destroy 
insects. 

5.  How  has  Jamaica  suffered  from  the  loss  of  birds? 

6.  What  are  the  arguments  in  favor  of  the  sparrow? 

7.  What  valuable  service  is  rendered  by  the  wood-pigeon? 

8.  How  does  the  crow  help  the  farmer  against  some  of  his 
worst  enemies? 

9.  What   experiments   in    planting   imported   seeds    have 
ended  disastrously,  and  why? 

10.  How  do  birds  of  prey  help  the  farmer? 

11.  What  curious  balance  of  animal  life  is  to  be  found  in 
India? 

12.  What  insects  are  entitled  to  the  farmer's  special  con- 
sideration? 


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GREAT  WORLDS  FARM 


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